Troy...I read right over the part about you using the Dexron. I originally purchased my GV for a D350 pickup, and installed it in that truck. My installation manual also had the sticker saying to use the GM petro or synthetic. I used the petro oil while it was in the truck. When I bought my 04 Dodge 2500, I pulled the GV out of my old truck and sold the truck. A few years later, I put the GV in my 71 GY3 Challenger. This time I used the synthetic GM fluid, and I'm much happier with the way it shifts. The Dexron probably wouldn't hurt yours,but I'd check with the GV techs to see.