I had an allison dealer do mine, but I used to just drain all the old ATF out I can, that way you might get 90% of the old fluid out. Then fill with new fluid. Run the truck for a while, then drain all the fluid again, that way you get like 98% of the "mixed" fluid out. Then refill with another dose of the new ATF and change filters. Then you have only a small % of old fluid in there, not enough to make any difference.LiftedDuramax said:I've searched till I'm crosseyed. Can someone give me a link (or just tell me) to how to flush an Allison transmission the correct way?
It's 12:30am I just love graveyards....NOT