hey guys im about to do the auto trans , transfer case and drive axle, fluids today. im going to drain em all completely and fill them up with new fluid. just wonderin if anyone has done this yet? i have the book and it says it looks easy to do? and my trucks already 7 inch lift so its easy to get under their. i have no i dea how old the fluids are. so im hoping it makes a differen in the way it drives. any tips?