W.W. Williams is the official Atlanta Allison Dealer. They have a location on Moreland near the GL site. They have been helpful to me in the past with M1078's, but I've never actually had to put a truck in their shop. As an actual Allison dealer, I imagine they are not cheap. That said, what is it that the transmission is actually doing or not doing? If you need a WTECII shifter, they are expensive (around $3000 from Allison). However, you can have them rebuilt for around $550 and get a two year warranty. You also need to keep in mind that many of the re-worked M1078's have transmissions made for WTECIII. The army had a WTECII compatibility / refit program that changed the internal wiring harness so the unit would work with WTECII controls. I only mention this because some of the techs at the civilian transmission shops don't know this and might make an incorrect diagnosis (or beat their heads in trying to figure out the craziness).