Originally Posted by NHDiesel

I'm with Gabe32. I personally HATE autos behind diesels (and autos in general, but specifically with a diesel). IF I was forced to have to run an auto, it would be an Allison. Be warned that not all Allisons are created equal. The ones used in GM trucks behind the Duracraps are very light duty compared to the commercial versions. They don't hold up that well in the GM trucks. Look for one out of a bus or other medium duty truck. I know medium duty Fords are available with them behind a Cummins, a 5-speed version, but I don't know if they are the same as the GM light trucks or not.

For what its worth, I'm so unhappy with my auto that I'm going through the trouble to swap to a 5-speed. My auto absolutely sucks for towing anything, and even daily driving is a pain with it. All it does is force the engine to run at high RPMs, wasting the low end torque. The only way my truck will move below 2000 rpms is once I get to 3rd or 4th and lock the torque converter manually and allow the truck to slow back down. Unfortunately the torque converter (and tranny in general) is very weak at low RPMs, so its easy to make it slip.

Run far, FAR away from autos for a diesel!

Jim