So if I do go with the manual and the lower 1st gear set (5.15) then it would be a good idea to stay with my 4.88's even when I get 35's? That would help out pricewise a whole lot. Can you tell a real difference having that lower 1st gear as opposed to the stock 3.83? I can't decide if I really want to go with the 5.15 or 4.31 with the 35's and 4.88's. Sorry for all the questions but I want to save as much money as possible in the end especially with the gas mileage and power. One last question, hopefully Marlin you can give me an idea on this. If I was to purchase the rebuild kit and lower gear set myself, is it that complicated to clean the tranny up and rebuild it in my garage? What special tools are involved besides the bearing pullers etc.? I have a pretty good knowledge of the mechanics of my truck and have done all the work on it myself (don't trust the dealer). I'm going to find a manual from a 3.4L and do all of this work on it, but I dont' want to drop the money and then find out someone else has to do the work. Thanks guys