Knowing this was going to be an issue, we loaded the transmission up with a Banks billet torque converter as the engine went back in. Once the truck was running, we babied it around town until a plan came together to get a transmission in it that would hold up to the abuse. To keep us moving forward, no matter the situation, we turned to the Duramax specialists at Pacific Performance Engineering, aka PPE Diesel, in Montclair, California.

002 chevy 2500hd allison transmission teardown

PPE Diesel has been in the business of hoping up Duramax trucks for decades, and their in-house knowledge of Allison transmissions is among the best in the business. With our power goals being sub-800 (we intended the project to be a hot street truck, not a racer) but still desiring the utmost in reliability, we skipped on the billet shafts but did go with PPE's top-of-the-line Stage 6 build.

In the next installment we'll dig deep into what exactly the Stage 6 is in comparison to the lesser transmission. For now, let's take a look at what was inside our transmission. When we bought the truck, it was claimed that the transmission had about 80,000 miles on a rebuild. Judging by the state of the rest of the truck, we doubted this. Interestingly, the transmission wasn't in as bad of shape as we had expected to see. Aside from a bit of clutch wear, it was actually quite clean inside.

The talented crew at PPE Diesel had the transmission out of the truck and on the bench in about an hour. And the tear down only took about an hour more. Check out the process below and be sure to check back for the next installment when we rebuild and reinstall our Allison.

003 chevy 2500hd allison transmission teardown