Why Your Diesel Tows Like Garbage (And How To Fix It)
About this episode
The hosts dig into why diesel trucks can feel great empty but “tow like garbage” once a trailer is hooked up. Real-world stories highlight bad shift/lockup behavior, especially when transmission strategy and torque delivery don’t match towing loads. They compare Aisin vs 68RFE behavior, explain how wrong throttle mapping and fueling can force harsh “dyno-style” bucking, and caution against oversized power setups (like a 13mm pump + big single) that make towing violent and unreliable. Key fixes include proper tow tunes, multiple tune levels, correct turbo/boost targets, and tow-appropriate tires/gearing.
Every diesel guy has been there. The truck feels great empty, pulls hard, and you love it right up until you hook a trailer to it. Todd, Will, and Myer dig into exactly why that happens and what you can actually do about it.
The conversation starts with a real story about building a 12 valve for power without thinking about what it would have to do. Big pump, big single turbo, five speed, and a trailer to tow. The result was exactly what you would expect from a setup built for the strip and not the highway. It towed, but it was miserable, and that experience sets up everything else in the episode.
From there the guys get into tuning strategy for trucks that need to work. Pedal mapping and throttle input are a bigger deal than most people think, especially when your transmission is mechanically activated and does not know your engine is making twice the power it was designed around. If your transmission thinks you are at light throttle while your engine is at full pull, you are going to have a bad time. Getting the tune and the transmission working together is step one.
Turbo selection comes up as one of the biggest places guys go wrong when building a tow truck. Oversized turbos that are great for making peak power numbers are often terrible for towing because they surge, they come on hard, and they kill drive manners under load. Compressor wheel clearances also factor into efficiency and reliability in ways most people do not think about. The right turbo for towing is not the biggest one you can bolt on.
Fuel system choices matter too. Massive injectors and multi-pump setups introduce complexity and reliability concerns that become a real problem when you are stranded on the side of the road a long way from home. For a dedicated tow truck, simple and reliable beats flashy every time. Carrying spare parts because you know your setup is likely to break is not a strategy.
Tires are another thing that can quietly kill your tow truck. Load ratings, tire size, and how they affect your effective gear ratio all play into how your truck behaves under a load. Going up in tire size without accounting for everything downstream can smoke a transmission and make towing miserable regardless of what else you have done to the truck.
The core takeaway is something the guys come back to repeatedly. You have to decide what your truck actually is before you build it. A dedicated tow truck and a street truck that occasionally tows are two completely different builds. You can have a modified truck that tows great, but the parts and strategy have to match the application.
If you are building a diesel and towing is part of the plan, this episode is worth your time. Subscribe on YouTube and follow the Power Driven Podcast on Spotify, Apple Podcasts, or wherever you listen.
Everything discussed in this episode is available at PowerDriven.com. If you are building a tow truck or a street truck that needs to work, the team can point you toward the right parts for your application.
Shop Power Driven Diesel: https://www.powerdriven.com
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