The Dodge Ram is a large pickup truck made for hauling and towing. Some versions use diesel engines, which are designed to pull heavy loads. It’s often discussed because it’s a popular choice for work trucks.
Car
Ram or Dodge truck
They’re talking about Ram and Dodge trucks and saying the transmission is often the first big problem area. If you push the truck hard or modify it, the transmission may not last as long as you’d hope.
“68 RFE” is the name of a specific automatic transmission used in some Dodge/Ram diesel trucks. People talk about it because it can have limits on how much power and stress it can handle before it starts having problems.
Clutch packs are the internal “grip” parts in an automatic transmission that make it shift and transfer power. If they’re not strong enough for the truck’s power or towing load, they can wear out or start slipping.
Tuning means adjusting the truck’s computer settings to change how it runs. If you tune it to make more power, the transmission has to handle more twisting force than it was designed for.
They’re saying there’s a ceiling to how much you can upgrade a transmission. Even if you add parts, the transmission still has physical limits, and the computer tune can only push so far before something gives.
A billet flex plate is a stronger aftermarket part that connects the engine to the transmission. People upgrade it when they’re making more power so it can handle the extra twisting forces.
The Ford Flex is a family-sized vehicle that’s built to carry people and cargo. It’s not a truck or a sports car—it’s more about space. It may be mentioned when people talk about how its engine and transmission are set up.
An Allison conversion kit is a set of parts that helps you replace your truck’s transmission with an Allison automatic. People do it when they want a transmission that can handle harder towing or more power.
ATS is the company they mention that sells the Allison conversion kit. That kit is used to help change your truck’s transmission setup for stronger towing or higher power.
They’re talking about a rough power level—around 700 hp—where the transmission may not last. Even if it works for a while, it might not be dependable long-term.
An “Allison swap” is when someone changes their truck’s transmission to an Allison automatic. It’s more than just swapping parts—you also have to make the computer and wiring work together so the truck drives correctly.
The “electronic side” is the computer/wiring part of the swap. It’s what makes the new transmission talk to the truck so shifting and driving behavior work properly.
“Integrate it with the truck” means getting the new transmission to work correctly with the truck’s computers and sensors. Without that, the transmission may shift wrong or throw errors.
Term
SETAC off out third row
This phrase is too unclear in the transcript for me to say exactly what it refers to. It sounds like it might be describing a specific option or configuration on the truck, but I can’t confirm which one.
“Manual mode first through six” refers to a transmission’s driver-selectable gear range where the driver can command specific gears. The speaker notes that the 6.7 trucks’ gauge cluster can display manual mode starting at 1st through 6th, which is part of how the kit integrates with the truck’s electronics.
This is the computer that tells the automatic transmission when to shift and how to manage driving behavior. The segment is saying the kit uses the newer control electronics so the transmission behaves consistently.
ECM and TCM are the car’s computers—one for the engine and one for the transmission. They’re saying the kit uses newer computer control so the shifting/driving behavior stays consistent.
Different transmissions take up different amounts of space. If the Allison is longer, the driveshafts have to be adjusted—like using a shorter rear driveshaft and possibly a spacer up front.
The driveshaft is the rotating shaft that sends power from the transmission to the rear axle. If you swap transmissions, its length may need to change so everything lines up properly.
A spacer is a small part that changes the spacing between components. Here it’s used to help the front driveshaft fit correctly after the transmission swap.
The 48RE is a particular automatic transmission used in some diesel trucks. People swap it out when they want a different feel, better towing, or more features.
A transmission cooler helps keep the transmission fluid from getting too hot. When you change transmissions, the cooling lines may need to be rerouted or adapted.
The torque converter cooler is cooling plumbing that helps remove heat from the torque converter area. They’re saying the install reuses the truck’s factory cooler setup.
Fleece coolers are aftermarket cooling parts for diesel transmissions. In this story, they used Fleece parts to help manage transmission heat during the swap.
A tap shifter is a way to tell the transmission which gear you want using quick taps instead of fully automatic shifting. They’re saying the Allison setup gives more driver control.
Miles to the gallon (MPG) tells you how efficiently a vehicle uses fuel. They’re comparing MPG results between the Allison-converted setup and the original 48RE.
Gear ratios are the “multipliers” inside the transmission. They decide how the engine speed (RPM) changes when you move the truck, so the truck can stay in the right power/torque range.
RPM range is the engine’s speed window where it feels strongest and most efficient. The transmission tries to keep the engine spinning in that sweet spot while you drive.
Hunting is when an automatic transmission repeatedly shifts up and down (or searches between gears) because it can’t decide which gear best matches the driver’s demand. It often feels jerky or delayed and can keep the engine away from the ideal RPM band.
Bogging down means the engine starts to feel weak and slow because it’s not spinning fast enough for the load. It’s usually a sign the truck isn’t in the right gear.
Locked up means the transmission is directly coupling the engine to the drivetrain instead of using fluid slip. It can make the truck more efficient, but if it locks at the wrong moment it can feel sluggish.
Gear spread is how the transmission’s gears are spaced out. If it’s well matched, the truck can stay in the “right RPM” for power instead of constantly searching.
A downshift is when the transmission selects a lower gear to raise engine RPM. That’s what restores power when you slow down or need acceleration, especially in heavy vehicles.
The valve body is like the transmission’s control panel. It directs fluid to the parts that engage different gears, which is why it matters for how the shifts happen.
Term
LML valve bodies
LML valve bodies are a specific version of the transmission’s hydraulic control unit used with certain GM diesel trucks. The point is that the newer-spec valve body is needed for the right shift behavior.
A matched pair means two parts are meant to be used together because they’re compatible. Swapping one without the other can cause the transmission to shift or lock up differently than intended.
A bell housing is a metal part that connects the engine to the transmission. If it cracks or breaks, the transmission won’t line up or mount properly, so you may need to replace it to get everything working again.
The output housing is the transmission’s “power exit” section. It helps hold the output shaft and connect the transmission to the rest of the drivetrain, so it matters when you’re swapping parts.
Allison makes heavy-duty automatic transmissions used in many diesel trucks. A six-speed Allison is a strong, multi-gear automatic designed to handle the big pulling power diesels make.
A core transmission is basically a used transmission you start with. Instead of buying brand-new, you use that unit as the base to rebuild or assemble a working transmission.
Term
vowel body
This sounds like it means the transmission’s valve body. It’s the part that controls how the automatic transmission shifts gears by directing fluid to the right places.
Drive shafts are the rotating shafts that carry power from the transmission to the wheels. If you change transmissions, you may need different shaft lengths or spacers so everything lines up correctly.
Cooler lines are the hoses that move transmission fluid through a cooler. They help keep the fluid from getting too hot, which is important when towing.
A “driveline change” is about whether you have to modify the parts that connect the transmission to the wheels. If the swap fits well, you might not need to change those connection parts.
“Sixth gear” is the highest gear in a six-speed transmission. The host is talking about when the truck gets into that gear and how that affects drivability.
“Lock up” is when the transmission stops using the fluid coupling and instead connects things more directly. That can make the truck feel more efficient and less “slippy.”
“Duramax” is GM’s diesel engine used in some heavy-duty trucks. The speaker is saying Allison transmissions are a proven match for those high-power diesel setups.
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Duramax
“Duramax” is a diesel engine used in some GM heavy-duty trucks. The point here is that it’s a common diesel pairing with Allison transmissions, and they’re comparing how well the setups work.
“Input/output” refers to the transmission’s shafts that connect to the engine (input) and to the drivetrain (output). Billet input/output upgrades are meant to handle increased torque loads without twisting or failing.
Automatic transmissions use planetary gears to change ratios. “P2 planet” is a specific gear inside that system, and upgrading it can help the transmission handle more power.
A conversion kit is an aftermarket set of parts that lets you swap an engine or transmission into a different vehicle. Different kits (and different truck years) can require different parts to make everything work together.
A transfer case is the part that sends power to both the front and rear axles on 4-wheel-drive trucks. It also determines how the drivetrain connects, including shaft/spline compatibility.
The output shaft is the transmission’s power-sending shaft. A billet version is stronger, so it’s used when the build is making more torque than stock.
A spline is the keyed, ridged connection that locks two shafts together. “23 spline” means the transfer case and output shaft have to match that exact connection pattern.
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Cummins
“Cummins” is a diesel engine brand known for making lots of torque. People often swap Cummins engines into other trucks and then choose a transmission like Allison to handle the power.
Term
PSC controller
A “controller” is the electronics that tell the transmission when and how to shift. In some swaps, you need a specific controller (like the PSC) to make the transmission work with the rest of the build.
“Clanky shifting” means the transmission shifts in a rough, noisy way. That often happens when the swap isn’t properly set up or the transmission doesn’t get the right signals to shift smoothly.
Term
can plus system
Modern trucks have computers that talk to each other over a shared wiring network. When an aftermarket part needs to work with the truck’s computers, it may have to connect into that network.
It means the part is made to connect easily without a lot of custom wiring or cutting. You basically plug it in and it’s supposed to work with the truck.
DFC Diesel is a company that supplies remanufactured diesel engines for trucks. They’re sponsoring the show and talking about how they build and warranty those engines.
Powerstroke is Ford’s diesel engine family used in many of their heavy-duty trucks. They’re mentioning it as another diesel brand that can be remanufactured.
A remanufactured engine is an older engine that gets taken apart, repaired, and rebuilt to work like it should. It’s usually meant to be a cheaper alternative to a brand-new engine, often with a warranty.
ISO 9001:2015 is a quality standard that companies use to prove they follow controlled, consistent processes. Here it’s being used to suggest the remanufactured engines are built under audited quality procedures.
Tow/haul is a mode or setup meant for heavy towing. It’s designed to handle the extra strain and keep the truck behaving predictably when you’re pulling a trailer.
Term
speed of air series
This sounds like a specific lineup of engines from the company, aimed at a certain kind of tuning. The name implies it’s about improving how the engine gets air to make power.
This is a brand-specific piston upgrade mentioned by DFC Diesel. The idea is that it helps the engine run more efficiently, so you save fuel and the engine lasts longer.
Valve train upgrades are modifications to the parts that control when the engine’s valves open and close. These upgrades are often used to support higher performance or better durability.
Lubricity is how “slippery” the diesel is inside the fuel system. If the fuel doesn’t lubricate well, parts can wear out faster and cause expensive problems.
Hot Shot Secret is a company that makes diesel fuel additives. In this episode, they’re promoting a product meant to keep the fuel system cleaner and protect it from wear.
EDT is a specific additive from Hot Shot Secret. The host says it helps clean the fuel system and improves fuel properties that can reduce wear and expensive repairs.
In an automatic, the torque converter is like a fluid link between the engine and the transmission. It helps the truck get moving smoothly without a manual clutch.
An eight-speed automatic has eight different gear ratios. That usually helps the engine stay in the right range more often, so the truck can feel smoother and respond better.
Term
68
“68” here is a nickname for an older Dodge/Ram automatic transmission. The host is comparing the newer eight-speed to that older 6-speed unit.
ETS here means an aftermarket kit that helps you install a different transmission into a truck. The host is saying it can fit trucks across many years without a complicated swap.
A flex plate is the part that connects the engine to the automatic transmission’s torque converter. When you’re swapping transmissions, people often upgrade it to make sure everything lines up and can handle the load.
Term
electronics all plugged into
They’re saying the wiring connections are straightforward. If it’s mostly plug-in, it’s usually faster to install and less likely to cause weird electronic issues.
An exhaust brake helps slow the truck down using the engine. It restricts exhaust flow so you get extra braking without wearing out the regular brakes as quickly.
Remote start lets you start the truck from your key fob or phone. The host is saying the swap doesn’t break that feature.
Term
68 RV
“68 RV” is a shorthand for an older Dodge/Ram automatic transmission model. They’re saying the truck’s computer can still run the same features as if that original transmission is installed.
Line pressure is the hydraulic “force” that clamps the transmission’s clutches together. Higher (properly calibrated) pressure can help prevent slipping, which is one of the main causes of rapid wear.
The pump is what makes the transmission’s fluid pressure. If it can’t build enough pressure, the clutches may not clamp firmly, leading to slipping and damage.
These are warning codes the truck’s computer sets when the transmission isn’t gripping properly. It can happen when you’re pulling hard, like towing, and the transmission can’t keep enough pressure to hold the clutches tight.
Term
built 68
“Built 68” means upgrading the transmission internals to make it stronger. People do this so the transmission can handle more power and towing without slipping.
Term
48 swap
A “48 swap” means changing your truck’s transmission to a 48-series automatic. People consider it when they want a simpler/cheaper upgrade than the biggest swaps, especially if they’re not towing a lot.
A “tune truck” means the computer has been adjusted to make the engine run differently for more power. It’s usually one of the first upgrades people do on a diesel.
Part
SMB intake
An “SMB intake” is an aftermarket air intake for the diesel. It helps the engine get air more easily, and it’s usually paired with a tune.
“CP3” is the name people use for a high-pressure fuel pump on Cummins diesels. If you’re making a lot more power, upgrading it can help the engine get enough fuel pressure to run correctly.
“Compound turbos” means the engine uses two turbochargers working together. The goal is usually better boost and stronger power across more of the driving range.
LIVE
Welcome to the diesel podcast presented by DFC diesel. Travis, welcome to the
podcast. How are you doing today?
I'm doing pretty good. Thanks for having me on.
I'm looking forward to chatting with you. I, uh, I follow you on Instagram and,
uh, you have a diesel shop here in Colorado and we had worked together a long
time ago. Um, yeah, yeah, you were my, uh, rapid HES like years and years ago
before we started the diesel podcast.
Yeah. I was thinking back and I was like, yeah, it was like 10, 11 years ago.
It's just time flies so fast. Um, which had a post about transmissions and I
thought, you know, it'd be great to, to talk with you and you own a diesel shop.
You've been in the industry a really long time and talk about 68 RFEs, but then
also the Allison conversion, which you were doing one at the shop.
So I thought it'd be great to have you on and talk transmissions for 67
coming trucks. Yeah, they have done several of them. So let's start like, I
know who you are. I know where your shop is located, but tell me a bit about the
shop yourself, um, what your specialty is there, and then we'll jump into the
transmission talk.
Okay. Um, we're just a local shop, a couple of people here. Um, in business, uh,
let's see, going on 12 years now. Um, we did just recently do a name change, but,
um, yeah, um, we, we don't really specialize in anything in particular.
Um, obviously I drive Cummins trucks, so I'm a little better with them, but, uh,
nothing stands out as a specialty, exactly.
Well, you're in Colorado Springs, right?
Yes. Yes.
So I'm sure you probably see a lot of different brands between like Ford and
GM and Ram. And, um, you know, with military presence down there, guys getting
transferred in and out. I see a lot of that stuff.
Yep. Military construction. We did plenty of it. So
I think with the 67 Cummins, like that was my first diesel truck. So
they're always real, it's just something that's special to me. And they were
always plagued with, I think kind of the classic problem when you buy a Ram or
a Dodge truck is you knew the transmission wasn't going to last. And if you did
anything to it, that was going to be one of the first things you had to do. And
for a while, I kind of, maybe you felt this way too. There wasn't, didn't feel
like there was a real complete solution with 68 RFEs. There was, it just seemed
like companies needed a lot of time because of how complex it was, some
limitations with how big clutch packs were. Like, what is it like in 2026 with
options you have and your customers have for upgrading a 68 RFE?
They're definitely getting better. It did take some time. It was a trial and
error. Fixed one thing on them. And then you'd find the next thing that was a
problem and it just kept snowballing. And then some of the things you can
upgrade as much as you want, but there's still limitations within the case and
what the transmission is capable of and what the tuning is capable of.
Is it, as far as upgrading them, is it really kind of based on power level? At
which stage you need to go to something? I think of like a billet flex plate or
in push after how intricate the build gets. Is it just based on power? Or is it
maybe also based on towing and then how hard the trucks are used?
Definitely, driver, what they use it for, what they have for power. You know,
stock trucks, you don't necessarily, of course, need to upgrade as much. But if
it's a customer that's a little harder on their vehicle, you might look at
definitely doing a billet in push aft. Flex plate is always a good idea. Dodge
has always made those out of tin foil. So always a good idea. In push afts are
very weak on them. So if somebody's towing heavy, definitely recommend that.
Anything in a tune truck, you're stepping into the in push aft range as well. So
and then of course, billet valve body on any of them, it doesn't matter what you
use truck for. It seems like much in necessity. It seems like when you look
at build 16 RFEs, they kind of come with everything you would need other than
you have the choice of like a billet in push aft or or a flex plate. But they're
pretty much coming with everything that you'd need for 2100
horsepower. Yeah, correct. I'll be honest, I don't like them at that power level.
They still are a question of the transmission. I have one for years.
Several different built units in it. And I don't like the wondering if I'm going
to make it home when I'm filling a trailer. It's still a 68 RFE.
That's what I was going to ask you is where, in your opinion, do people need to
start thinking about a different transmission entirely as it relates to
power, which I know we're going to get into the Allison conversion kit that
ATS has. But what power number do you say now you just got to think about
something different here?
Probably that 700 horsepower range is where you're really, in my opinion,
playing with fire. I know there's plenty of people that rate them higher, say the
last higher, but it's never a long term solution with a 68 RFE.
I tell every customer, you know, look for your warranty and how easy it is to
work on with a 68 RFE because you're going to use it at some point.
I don't care who builds it, you're going to have that transmission out for
warranty at some point.
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And with that Allison swap like that, I've spent some time researching it and
it, there's like tons of options that ATS has, like from a complete kit, if I
understand it correctly, like get a transmission, the bill housing, the
electronic side, which I think is what really helps that thing come together
is being able to integrate it with the truck. What, like with the truck that
you guys had posted on Instagram, tell me a bit about like that customer's
truck, why they, like did they come to you and say, hey, I want to do this
Allison swap? Did you guys offer that suggestion as something either for their
power level or where they were going to take the truck?
Which truck are you talking about specifically? Because I've done several
of them in the last few months.
It was probably the most recent one. I think it was on, it had just delivered.
So it was like on a pallet and you had posted a picture of it.
Okay. Yeah.
That's actually not a 68 RFE replacement. That was a 48 RFE replacement.
We were doing the Allison conversion as well as the SETAC off out third row
is for him. Oh, cool.
So that was going, that was going in behind a 5.9.
Correct.
06, 5.9 truck.
So that's, I think that's really, like I said, I spent a little bit of time and I
saw that there was some like 5.9 kits that they had and then 6.7, like on
the drop down menu, you could pick what year you have, do they behave
differently between or the driving experience? Is it different between a
5.9 and 6.7?
No, not really. Like they're super integrated about the only thing that
makes a difference in the kit is the 6.7 trucks. The gauge cluster has the
option to show manual mode first through six. The 48 trucks, obviously only
have one of two. So you have to have the, don't have to have it, but the
banks I dash that they integrate with it to read manual mode what year you're
in, but otherwise they drive very similar.
The transmission control is all done by the latest T87 ECM or TCM from for the
Allison controller. So they're going to drive all the same. It's just where
they're getting inputs from. As far as truck side, what the information is.
So on that 5.9, like from an install perspective, is there anything that you
had to do separately or did everything that you would need to do that at the
shop, it came in the, in the kit itself?
Everything comes in the kit minus drive shifts. They need to be obviously the
Allison's a bit longer than the 48RE. So you have shortly rear drive shaft.
They do send a spacer for the front drive shaft. I don't use it. I just have the
front drive shaft done when I did the rear drive shaft, but you know, for
somebody doing it in their driveway, definitely if you can take out a 48RE,
you can put in an Allison. It is that easy.
And it hooks up to, well, when we talk about like the transmission cooler, does
it include lines? Do you have to do different cooler lines? Like how do you,
how do you integrate the cooling side of it when you do the install?
They do send lines for, their kit is fairly universal. Like they include the
lines for the 6.7 and 5.9 and 3rd gen stuff, but it just integrates to the factory
torque converter cooler on the side of the block, heat exchanger, and then splices
into the other factory line on the 48RE. Quick and simple.
The two I've done, what I've got my personal truck done with Allison conversion
and the one I just did for that customer. I actually use the fleece coolers
and their line kit. And then I reroute the lines to the passenger side where
the Allison has their outputs anyway.
Okay. Now on your truck, how do you like, like do you tow with it as a daily
driver? Like how do you use it? And then how do you like, like the
Allison 1000 in something you're driving every day?
It is, I mean, it's a mega cat newly truck and I set it up specifically for
towing. But for some reason I do daily drive it every day. And it actually does
fantastic. Like I say, it's a towing truck transmission, but I mean, all the
built 48 you want out there, there's their dumb transmission. They don't have
the control you want. They don't have the tap shifter. So as a daily driver, the
Allison works fantastic too.
My cruising back and forth on the interstate, I've been getting, you know,
18 to 20 miles to the gallon out of an 8,000 pound newly truck because of that.
Allison conversion. I never got anywhere close to that with the 48.
So definitely a daily driver friendly, but it also chose amazing as well.
I was just gonna ask you that with like the gear ratios that are in an Allison
and where it puts you in the RPM range, how that worked with your particular
truck or with with a Cummins engine. I'm sure it's not stock. You probably have
some upgrades on the engine side a little bit to give a little bit more power.
So how does that all play together as far as the driving experience?
It is super seamless. Like the 48 always seems to be hunting if not in the right
gear, you know, or bogging down because it's locked up and you want to go
somewhere. The Allison has the right gear spread to maintain the proper RPM range
for that truck. And it's always in the gear that you want. But you don't have
to think about it. You know, 48's are, once they're locked up, if you slow
down, they take forever to downshift and get back in the right gear and back
in the power range. The Allison will always shift into the gear that you
needed or want it to be in. Like it's always just right there ready to go.
Are they, I guess it could vary a little bit because I think ATS has a kit
where it includes everything but the transmission. So somebody could, you
know, if they built their own or something, they could run it. But are
they 5 speeds or 6 speeds?
They are based off of the 6 speed. Like the ideal situation, you would have a,
they use the later LML valve bodies. So like the 15 and up trucks, they're
going to use that valve body, that converter. Valve body and converter
have to be a matched pair out of those trucks. But if you wanted to go to the
junkyard and buy a 2015 GM transmission, you could definitely do that. One of
their guys that actually helped them with the pioneering of the Allison
conversion, the controller side of it. That's what he did. He bought a
transmission out of broken bell housing. So you get a new bell housing, new
output housing and he put a junkyard like $200 transmission in his truck and
that works flawless. So it's so cool to be able to take like those trucks,
like especially the five nines is like they have just enough control that you
can make really good power and like the sky is the limit for what you want to do
on the performance side or however you want to, whatever you want to turn it
into. But it's not so complex that you have to get into some of the emissions
controls or some of the other things like the six sevens have. But then now you
can take this six speed Allison, which it's been proven at different power
levels and different uses for so long, be able to take that technology, combine
the two. I bet it makes a really, really sweet setup.
It definitely does. Yeah. And that was my whole selling point. You know, I had
my 2016 truck with a 68 RFI forever. And I like the truck like super nice truck.
But I always had that question, throwing a trailer if I'm going to make it
home or if I'm going to have to put it on the train. Yeah. And I happened to find
a smoke and deal on this 0659 mega cab truck. And at that time, my 2016 truck
was just living on the trailer anyway. So I figured I'll do the Allison swap on
this. I've got a core transmission ready to go. I actually built mine and then
swapped in their vowel body and accessory stuff and just make a tow truck out
of it. Not worried about if I'm making a whole. With the six sevens, I
imagine the install is exactly kind of like the five nines minus a few little
things here and there like with the lines, the bell housing, everything's
included except for drive shafts where either has a spacer for the front or you
got to change the length on the rear, but just a seamless install on those
trucks, too. Yeah, they're even better because 60 RFEs have the cooler lines
on the other side where they go anyway. Like the 13 and up trucks. I did one of
those a couple months ago. It's just got little jumper lines plugs in right where
the temperature, the thermostat block is and obviously gets rid of that thing
too because that's an issue, but super clean and simple to install.
The 60 RFEs real close and length to the Allison. So there's not much of
driveline change there. Like you could probably get away with not changing
the driveline. What do your customers say? Like the first time they go for a
ride after you do the swap and you hand them the keys? 68 customers are
amazed because everybody knows how 68 shifts. They just ramble through the
gears that get to lock up at like 40 miles an hour and sixth gear and
they're just never where you want them. So everybody is super impressed, super
amazed with this, with an Allison versus a 68 RFE. I think if I had one, that
would be something I guess I would probably look at doing it right away,
especially if I had plans to do compounds and until fuel or kid and some
other kind of things, I would just skip. I think I would skip the 68 RFE build
and just go straight to something that
Yeah, most definitely. I mean, 67 trucks can make five to six
hundred horsepower with just tuning. So you start adding other things at 68
will never be applied.
With like throwing power at them, is that something it could be a 59
customer or just maybe yourself, maybe it's a project that you have planned or
something like that. Would you run that six speed Allison behind some of this
eight a thousand, 1100 horsepower or something kind of in that range?
Oh yeah, most definitely. I mean, in Duramax platforms, we've done
Allison's forever with, you know, a stock in push half the whole 700 horsepower
all day long in an Allison. Duramax has a little bit more work, but still you
compare the shafts, ones like to burn a pencil to a broomstick, you know, it's
huge differences. So I would have no concerns running a high power engine
in front of an Allison at all.
I think some of those options that I saw, like you can get a billet on the
Allison, you get a billet input output, P2 planet, like you can go pretty far
with the billet upgrades inside of it, if that's the kind of bill that you need.
Yeah, depending on what year you have on those conversion kits or what truck
you're putting it in, like 48 RE trucks are going to come with a billet
output shaft anyway, because they've got to build their own for the 23 spline
transfer case. So
That's cool. And there are people for so long that I had mentioned before
the podcast that like that was the thing is somebody wanted and people do
build them now, I guess is like you take it forward, you put a Cummins in it
and then they wanted an Allison transmission. And I know in the early
days there were some people that did it, but it wasn't it wasn't very refined
or integrated like this kid and what you've described where it has literally
everything that you need. And it's just it's almost like factory. Like that's
what it came with. Oh yeah, for sure. Like I've done the older D stroke kids
when I did six liter conversions with, you know, either a common rail or 24
valve and an Allison. And I've done I've dealt with a couple of the CA conversion
kits. And they're just like the D stroke kit is so much wider. I just send you
the PSC controller and let you have at it, which is not a lot of fun. And they
just they never really worked right. They're they're just clanky shifting
because they don't have the inputs that they need. So they just tell the
transmission shift here, here. And they don't have any
like dynamic tuning to it. It's just banging through gears. It's not very
comfortable to drive. And they really don't work that great. But like the
ATS setup is if you can change a transmission, you can put one of these
in the 48 kits are the part of 48 replacement kits are the hardest to
install, because there's two wires you have to tie into the can plus system.
But the everything later, the 67 and fortune stuff is complete plug and play.
Common question we get from you guys a lot is, Hey, I need a diesel engine. I
either, you know, I can't wait this long to get one or normal place I get stuff
from it. It just takes too long or I don't they don't have the parts in it that I
need. Maybe my truck's not stock or I tow heavy with it. I don't want to go back
with just a stock engine. DFC diesel is a sponsor of the podcast. We worked with
them, you know, hand in hand on doing episodes, answering technical questions.
They have a complete lineup of Cummins, Duramax and Powerstroke,
remanufactured engines that are set to a standard of ISO 9001 2015 standards,
which is a huge deal in the aftermarket. And there's certain levels of quality
testing validation that are required for that. So you know, when you get one of
those engines, the type of quality that's built behind it with an industry leading
warranty, that's really comprehensive. And you know, the other thing with that
is, you know, sometimes the options that are out there, it's just it's a basic
OEM engine. You want a little bit more, you don't want to have the same failure.
Again, so there's a bunch of different series of engines that they have
from core street, tow haul, and also the speed of air series, which we've covered on the podcast
before. There's a lot of really cool benefits to it. And if you have questions about that,
reach out to them. If you don't know the type of engine that you're looking for,
if you go to DFC diesel.com, there's a ton of info there, you can send an email
or you can reach out to them. Also, they're working with speed of air pistons,
which it's the only piston that pays for itself. And there's a lot of really cool
technology behind it. So you can add that into your build and be able to get better fuel economy,
you know, increased power, increased torque and better engine life out of it.
You know, some of the most common engine applications or series of engines that they have
with that lead time, a lot of them are in stock or they have really short lead times.
So you can check your favorite retailer or go to DFC diesel.com,
check them out to see what's in stock, see what you can get. If you have questions,
maybe you want to do, you know, something that's outside of the normal series of engines,
they have tons of choices for rods, cranks, pistons, valve train upgrades, tons of different
things. So if you're in the market, definitely make sure and hit on over and check them out.
Hey diesel fans, I wanted to chat with you about diesel fuel. It's something we've talked about a
lot on the podcast and specifically ways that it can lead to a lot of costly repairs. And the main
reason that we have these issues is a lack of lubricity. Our friends over at Hot Shot Secrets
have developed a formula that boosts performance and then addresses this issue. So whether you
have an old truck, new one, something anywhere in between, we all face this issue. Hot Shot's EDT
is a six in one formula. It cleans injectors, boosts C-tane, and it has four times the lubricity
as our leading competitor. So it's a great way to be able to stay ahead of the maintenance curve,
avoid those costly repairs. And the best part is it does the work for you. So all you do is add it
to your regular fuel up schedule and it's doing all the heavy lifting. So you don't have to worry
about some of those issues that just come with diesel fuel anytime we buy it from the pump.
If you go to hotshotssecret.com, use code dieselpod20. It'll get you 20% off your order. We really
appreciate the team and our friends over at Hot Shot Secret offering this discount code just for
you guys. So if you're in the market, head on over to their website, use code dieselpod20 and get
20% off your order. I think it's so helpful like on the aftermarket side to be able to have
like all the technology that it's already there, like all the work's been done with,
what to do with the converters, the valve bodies, the clutch material, the just everything's already
been done. So you can just take what's already proven and get it into a new truck versus like
one of the big stories the last couple years has been the new eight speed that Ram has and it
seems great. It seems like it holds a good amount of power. It seems like a definitely a better
option than the 68 was, but it's still so early in it. Like sometimes when I ask companies or
have a guest on like, what's the potential of it? They don't really know because nobody's really
pushed them that far yet. So I think in that, gosh, I think that kid covers five nines. So
back to the early 2000s all the way to, is it 2019 to 2024? I think they have the ETS kid can
accommodate. Yep. All the way up to 2024. Yeah. So you can have a 20 year range and be able to
take a proven transmission platform and bolt it behind your truck. Yeah. And there's not a
bunch of complex adapter plates. There's not any grind in the block and using a six liter starter,
nothing like that at all works with the Dodge stuff. I mean, I always upgrade flex plates when
I'm in there, but you can even use the factory 48 or reflect. They are simple. They're both in.
They're easy. When electronics all plugged into a valve body connectors.
That's what I was going to ask you. That's what I was going to ask you next is like,
as far as with the factory electronics, like the exhaust break and everything else, like that all
still works with the kit. Remote start. Everything works exactly like it has a 68 RV in there or
48 RE. As far as the truck knows, it's still running the same transmission. That's so cool.
Yeah. It's super clean to install. And for people installing them for the tech, it's nice too,
because it is that easy to install, but you're not. I have yet to receive instructions on how to
install these kits because you don't need them. Like it is that easy. Not charging the customer,
20 hours to do a conversion. You're charging them a little bit more than you would for just
swapping the transmission. That's a really good point because I think that gets overlooked a bit.
I think by truck owners, even myself, as I look at the price of the transmission kit,
like say this Allison swap, and then if I take it to a shop or I call them or something like that
and say, hey, I want to do this, like if they haven't done one, they might not know,
is there more time? Is it a ton of time extra? Is it a little bit? So I think it's really helpful
to know. It's just a little bit more than a regular R&R. Yeah. And that's just for
mounting a couple of modules and running some wiring. But that's all super, super easy to do.
To step back for a second, because I can imagine someone listed in the podcast,
they've got a 67 and they're thinking, well, I've been seeing these
upgraded turbo kits or these compound kits. I want to make some more power,
but I know I need to address the transmission first. And they wonder, how long can I get by
on this stock transmission? Say they haven't done the compounds yet and anything like that,
but they're just wondering, can I make it live longer? Can I not make it live longer? In my
opinion, I guess what I had seen is that once those slip once, it's pretty much, it's quickly
downhill after that. There's really no way to kind of limp them along or make them last. It's just,
you got to keep the power level down, drive it smart, not be too hard on it,
and then just swap it over. But have there been any tips or maybe tips isn't the right word,
but anything that you would say as a shop owner can help them live a little bit longer until
they're ready to go down this route of upgrading the transmission? Definitely,
valve bodies are a big thing on 68 RFEs. They're just made of bubble gum wrappers.
They're terrible materials. And anytime you get across the leak, you're going to burn a clutch
and 68 RFEs. As soon as they slip a clutch, it's going to glaze it, and then it's going to start
happening more often and faster. So definitely a valve body. Anything you could do to increase
line pressure on those. The big problem I had with mine for years, even after I had a built
transmission in it, was the pump as well. Granted, that's a little more work. It's not a,
you know, pull it off when you do a transmission service kind of thing. But the pumps in those,
when you're at cruising speed, higher RPMs, and the fluid gets hot, they do not maintain
the pressure and volume that they need to keep the clutches engaged. So that's where you see
people that'll be towing or whatnot in higher gears, higher RPMs, and they'll start getting
clutch slip codes because it just does not have the volume to push out into that transmission
and make it hold the power. Yeah, they don't, it doesn't seem like they lend themselves to being
able to kind of limp them along and make them survive a little bit until you're, you know,
got the coins saved up to do the the built transmission. It just kind of happens right away.
Yeah, unfortunately they do. A lot of times it's because it's already been doing that a little
bit. It just hasn't set a code yet. And then by the time it sets a code, it's way too late. It's
controversial question to ask you, but I trust your professional opinion on it.
If you had a 6.7 and you were planning on say over 600 horsepower with your build,
would you just go immediately right to an Allison swap versus a built 68? Or I'm not sure how popular
the 48 swaps were. I know at one time they were, I did one, I liked it, but I wouldn't want to toe
with it. And it wasn't very fun to daily drive. It was just kind of fun to, you know, floor it,
go down, you know, in a straight line. But like, would you suggest just going straight to the Allison
swap if you plan on that 6.7, 8.900 horsepower range? I think it really depends on what you're
using the truck for. If it's a, you know, fun daily driver and you don't toe with it,
you know, there's plenty of 48 RE parts out there and you can probably do a 48 swap cheaper.
So that works plenty fine for people that aren't toeing. But if it's something that you're going
to turn up the power and especially if you're going to toe with it, yeah, just step right to the
Allison. Don't waste your time on swapping 68s out a bunch of times. Now, like with, with your
duel you were telling me about your, your 2016, how'd you set that up to toe? Like what kind of air
and upgrades did you do to be able to? It was a, it was just a tune truck, you know, the obviously
the basic bolt-ons, SMB intake, you know, little things like that, but nothing as far as I never
got put ejectors on a bigger CP3 compound turbos, anything like that. So it was purely tuning and
transmission tuning. And then when I did the Bill 68, it had the valve body down and pumped on and
all that kind of the necessities for a 68, but it was still always a question. Yeah.
Yeah, I think, well, I think people like in this region, Rocky Mountain region, or that live at
elevation, they understand the big difference. Like we were talking a little bit before the podcast
about the Pikes Peak race and, and you were there and just how much it changes performance and,
you know, diesels make great power and make great torque and they still experience that loss
as you go up in elevation and where compounds can really, I guess, give it back to you or increase
like your EGT control. They're just so much, there's so many benefits you can get at elevation
with a compound set up for like a daily driving towing setup on these trucks. Yeah, that's another
consideration too. If you're somebody that lives a C level, it's going to be a completely different
power requirement for towing. You know, there's people all the time I talk to that toe with a
big single S 400 on their 67, which I have one at elevation and it's terrible to drive. I hate it.
I would never go with them, you know, but people down there do it all the time. Yeah. Up on the
mountain, it is way different. Yeah. For sure. Yeah. When I was that first 67 that I had,
everyone that I knew in the industry, most of them lived at C level and they're like,
if I would race it or do something like that, but daily driving it, it's like two pounds of
boost on the highway and it's like, it's either on or off. There was no middle ground with it.
It was definitely a challenge. Yeah, definitely is. They're just not for high elevation or for
towing in my opinion. Compounds are always the right answer for towing.
Now, with like to step back, I guess for diesel kind of performance in general,
and as a shop owner, you know, where things are at in 2026 and
like parts and upgrades that people ask you for, do you find that
now there's more, there's more solutions you can offer your customers and it doesn't have to be
transmissions. It could be with like fuel systems and like you mentioned the fleece transmission
cooler. I know they have like a lot of fix it products for people that start to get some mileage
on their truck and want to do it. I'm really curious like what your perspective is as a shop
owner and what you're able to offer your customers, keep these trucks on the road,
keep them running. Maybe they don't want to go spend $95,000 on a new truck. They want to
put some new life into that LML or 67 or you know, something like that. Is it pretty good
like with aftermarket support that you're finding? Yeah, most definitely. There's fleece is a good
example. They make a lot of little parts that are, you know, like a lot of times I'll sell them as
hey, do this before it is a problem, especially like 67 intercooler boots or intercooler
pipes, you know, it's just they make a lot, a lot of things that are little niche products. They
help keep the truck reliable and I do see a lot of people that are, you know, they don't want to
spend $1,500 a month on a truck payment for something that's still going to have issues. So
there is a whole lot of people going back to pre-emissions or early emissions trucks that
they can still do something with that have fun. And I mean, even myself, that was part of the
reason I went from my 16 back to the 2006 is I can do whatever I want with it for the most part.
Yeah. And there's plenty of support for that's been just on the pod, like doing a podcast.
I've noticed a lot of people over the like last four or five years that are like,
do more six liter content, do more 73 stuff, do more VP 44. And I think it's for that
exact reason that you mentioned this one, the simplicity and they don't, I think they'd rather
spend $20,000 or $30,000 on a truck that they know is going to last versus spending that extra
money on financing a vehicle and potentially having issues that they read about or see on YouTube and
stuff like that. I just want to keep it simple. Yeah. Most definitely. Right. They would rather
like say spend $20,000 by a truck and then another $20,000, $30,000 to upgrade it and make it
for sure reliable instead of, oh, they're trying to get to a job site or they're hauling this
across the country and now their trucks broke down. They got to take it to a dealer for warranty work
and they're still making a payment on it, but you know, if I can't afford to replace it now,
so it's kind of stuck.
See on those third gens, a question I was curious about is,
do you find that there's issues or problems finding things that Ram no longer supports,
like maybe it's electronic stuff, maybe it's ECMs or PCMs. Do you run into any parts on
third gens that are just difficult to find? So if someone is thinking about getting one of
those trucks and they're going to be taking it to a shop or they're doing some upgrades or
maintenance on it, they could be prepared to know, hey, it might be difficult to find these
couple of different components because they're just, they're tough to find out there.
There are some things that are, you can't get OEM anymore, but for the most part, the aftermarket
suppliers have stepped up and made a replacement or a better replacement for sure on those.
There's not very much that I can't get anymore on those, whether it be OEM or an aftermarket
support, there are certain things like ECMs are, you can still get them from the dealer,
but they're obscenely priced, so you always go aftermarket for something like that, but there
is companies that have stepped up and made a decent replacement easier.
That's good to know for someone thinking about getting one of those trucks and
being able to have access to it. I know some episodes I've done about like the 73 OBS trucks,
some of those guys like door hinges and different things they've had trouble getting and aftermarket
companies have stepped up and offered them, so they have, they have solutions. So I was always
curious on the third gens side because I think that's like, it's still, I mean, even when they
were out, they were the holy grail of diesel trucks to get if you wanted, if you wanted to
come in and especially if you wanted to make power with it, like that's what you bought and
you're 20 years later, it's still the same thing. So it's not, it's not going away.
Yeah, for sure. And there's, there's better tuning support out for them now,
you know, people are getting in trouble for tuning them. So it's simple and it's easy
and you can make any amount of power you want out of them, you know.
Yeah, that's still, I still have that dream of one day, like, finding, I don't know,
on bring a trailer or something like that, some barn fine 1500 mile 2006,
2007, 59 Yeah, you get the time machine. I think I saw one recently,
it was like a, I don't remember who posted it, but it was like a gold one G 56 and it only had
like 3000 miles on it. And I thought, Oh, that would be a perfect truck to,
perfect truck to get. I know they're out there. They're just kind of tough to find.
But even if it had higher mileage on it, like you said, I'd rather,
I'd rather go to your shop and have you give me a bill and do all the things I want to it,
then go down to the local Dodge dealer, Ram dealer. And I'm seeing a lot of people too that'll,
like they'll find a decent enough truck, even if it's got a little more miles on it,
the drive trains are pretty solid in those, you know, do this steering linkage and suspension
stuff. So to fix that, there's plenty of options for fixing that. And then they'll buy a truck
with a bad transmission or a bad engine, knowing that they're, they got a good deal on it. They
like the truck otherwise, and they'll just upgrade the engine, you know, put a better
transmission and begin with and know where they're at. And they're still, you know,
$15,000 into a truck that already has this part on it that they want.
Yeah. Yeah, that's an excellent point is, you know, even if, even if it needed an engine,
there's so many options for, I mean, to upgrade them as crazy as you want, or just have something
reliable for the street or for towing, you can get those a lot cheaper than a 2026 Ram 2500.
Oh yeah, by far. And I mean, I've done it to my truck and I've done it to several customer's
trucks. It's something I kind of specialize in most third gen 59 trucks. Well, all three
of mine are all 67 trucks now. So 67 long block swaps right in, you got to change
injectors and send it down the road. And they work way better than a 59 I hardly even
build a 59 truck in shopping. Like I convert everybody to a 67 because it's
quick, it's easy, gives them more power, more torque, and it's a lot happier truck.
I bet at elevation, they really like that extra displacement for. Oh yeah, for sure. Driving
a turbocharger. Yeah, you can get some people that can do their S 400 swap then on a earlier truck
and still drive the thing at elevation, just because they do have bigger displacement.
It's really cool how
like how almost seamless between 59 and 67 a lot of the parts or conversions or
just upgrades you can you can do on them from like you just mentioned being able to take that
67 block and put it into one of those older trucks. And then, you know, that opens up
the door to different turbochargers you can have and just different things. And even with like
transmission swaps, like the Allison conversion we were talking about, I don't really find other
brands have that kind of deep of a catalog or, you know, people who have asked for it and after
market companies have stepped up and said, okay, we're going to offer you a six speed Allison
conversion that just bolts right in other than your drive shaft potentially. And that's something
really cool about the platform. Yeah, most definitely. And the controller is very adaptable
as well. The translator module that ATS uses the same translator module that they use for their
8 HP conversions in the Hellcat powered stuff. And also the Jeeps that they've been doing,
you know, non Hellcat stuff. And it's also the same controller for their 8 AP, the new A-Speed
and the heavy duty ramps that they've installed in their fifth gen in place of a ICEN. Like,
same controller, it's very adaptable. It just takes the information from the truck,
puts it into the module, spits back out what the transmission needs, the transmission puts
its information into it, spits back out what the engine needs, so everything functions together
and it's pretty seamless. So it's pretty much just translating
whatever the computer needs to see to be able to operate correctly to have these OEM features.
It's just translating between the two, which didn't exist before. And that's kind of where
you had mentioned some of those early like Allison conversion kits, either weren't in
the right RPM range, it didn't shift when it should have, and you couldn't really do anything with
it. Verse now, it's translating this information to just make it like an OEM, like it came from
the factory. Exactly. Giving all the information that it actually needs to function properly instead
of just banging gears and calling it good. It's so cool. I've been wanting to talk about this on
the podcast for a while because I know there's just such a 2007 and a half to 2024 trucks,
they get into that situation where it's so easy to make power with a 6.7, they get over that 6.700
horsepower mark and it seemed like forever people would say, well, I go with a 48, I don't know if
I just want four speeds, like I do tow with it a little bit. And there was really no middle ground
or they would like you experience with a 68 RFE is you could just keep having issues with them at
those higher power levels and you just don't want to deal with it. So it was cool to hear your
perspective as a shop owner, someone who's done one and then have done them for your customers
of just how it works, what's included. And there's another viable option on the market to
support those guys. Yeah. And Clint even told me I could say this, when it comes to warranty on
an Allison conversion, he doesn't care. You can sled pull with it, you can drag race with it,
it does not matter. What you do with it, he just does not see an Allison fail, so he doesn't care,
he'll still warranty it. I had a Duramax once with a 6B build Allison, it was probably my
favorite upgraded transmission I ever had for daily driving and just being city driving,
being on the highway. It was just so predictable, so nice. And I compared that to an upgraded 68
that I had had and even 48 RFE or 48 RE. And it was just such a different driving experience
to have that. And I imagine with your truck and the customers that you have,
and the technology that's much farther along now, it's probably a really sweet setup.
It definitely is. It drives like a Duramax as far as transmission is concerned,
but you get all the power and stuff that you want from the coming side too. It's a very good
marriage they've made there. The best of both worlds. And like I said, it's not just that it
all works together, it's so easy to install. It is very seamless, it's a very good package.
And it, like you don't have to hack up a bunch of stuff, you don't got to be
holes in your firewall or build a brace for it or mounts or anything. It literally,
you unbolt the transmission, bolt the new one in. And you just set it down the road.
I know we get a lot of plays from the Colorado Springs area on the podcast,
and I always like to be able to connect our audience to our guests because there's probably
questions I didn't ask you about the swap that I should have asked you that someone's like,
why didn't you ask him that? So I always like to have an opportunity for people
to be able to connect with you. What's the best way to reach out to Peak Diesel,
connect with you, is it through social media, calling you guys, jump on the website, maybe all
three? Yeah, any of them work. You can call us, you can text us down the phone number, email,
social media, whatever works. We're pretty open to any of them.
As far as the website is at peakdiesel.com? That's peakdieselco.com.
Okay, so very cool. Well, I appreciate your time today, Travis. It's great to connect with you
from, you know, way back in the day. I remember chatting with you and your business and stuff,
and like I said, I saw that picture you posted, and it just reminded me, hey, I've got to do an
episode about this conversion, because I think it's something that it's viable, it's cool,
it's seamless, and someone might be interested in it, and they're either,
maybe they don't want the 48RE, maybe they're tired of 68s, and they might not have heard about it.
So it's great to connect with you and chat with you today. I appreciate your time.
Yeah, let's go talking to you. Don't forget, diesel fans, make sure and head on over to
kershaw.kausa.com. Use code TDP402026 for 40% off MSRP. It's a great way to save some money,
get some cool gear if you're on the market for a new knife for hunting, fishing, EDC,
round the job side, round the house. Then we've got you covered with a bunch of different choices
for blade steel, blade shape, different handle designs, different opening mechanisms.
They've had a bunch of new releases in 2026. So again, if you're in the market,
head on over to kershaw.kausa.com. Use code TDP402026 and get 40% off MSRP.
Also want to give a shout out to some of our Patreon supporters, Robert, TSW, Diesel, John,
all of our other Patreon supporters, all of you who subscribe on YouTube and podcast apps,
follow us on social media. We appreciate all your support here in year 10 of the Diesel podcast
and look forward to bringing you more of the content that you want to hear in 2026.
About this episode
Travis joins The Diesel Podcast to talk Cummins transmission choices, starting with why 68 RFE durability can fall apart under towing and higher power. The hosts explain how internal hardware limits, clutch-pack sizing, and hydraulic issues like valve bodies and pump problems shape reliability. They then pivot to Allison conversions—especially ATS kits—highlighting electronic integration, cooler-line plumbing, and drivability benefits. The discussion also covers fitment differences, translator-module signal coordination, and why some owners skip building a 68 RFE for compounds plans.
The 68RFE has been one of the most debated transmissions in the diesel
truck world. Some owners have had great luck with them, while others
start looking for alternatives as power levels increase or reliability
becomes a concern.
In this episode, we talk with a diesel shop owner about the ATS Allison
transmission conversion for Ram Cummins trucks. We discuss why some
owners are making the switch, how the Allison integrates with the
Cummins platform, what the installation process looks like, and how it
compares to the factory 68RFE and older 48RE transmissions.
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