Ok I just bought a 99 Xcab long box 4x4 with an auto, Been reading alot on auto upgrades. My question is why doesn't anyone run an auto with 100% lockup? What is the reason for the difference in lockup percent? The truck has 101000 on it and I'm looking at changing converters and valve body. The truck was owned by a woman and I can't find a sign of a brake controler ever being in it so I don't think it has been worked hard or bomded. I am woundering because I am looking at putting a box on it.