[cleatus12r]

You have some very valid concerns. If I may, I would like to use my personal experience to help you make a decision.

I have an '01 with the "mechanical diode". My truck now has 128K on it and I became the second owner at 62K miles. The first owner chipped it immediately (Western Diesel Performance) and used it to haul a horse trailer, much like I have been doing since I bought it. If it's not the horse trailer, it's something that puts me at a combined weight of at least 15-16K with the occasional 20K tow. I also made a 200 mile trip hauling an M35A2 "deuce and a half" truck grossing 32K.

I don't race it or abuse it. I have run 6 different types of tuning since I bought it and it's still all original.

I also have some thoughts concerning the valve body craze that everyone seems to have. I don't like the thought of firming up shifts and making them quicker when it comes to stock parts...especially high mileage ones. Knowing what goes on inside an automatic transmission has kept me from modifying mine. My concerns have to do with durability and I believe that a stock transmission is not up to the task of shifting as quickly as a "built" or freshly built 'box. Take it for what it's worth. An aftermarket valve body WILL NOT make the transmission stronger.

The risk of breakage exists even with a stock truck. Cognizant operation will ensure a long life with ANY form of tuning.....recognize that certain shifts are more "fragile" than others (1-2 mostly) and that forced downshifts are hard on stuff.