My truck is '02 DC w/SC,TRD Header&Exhaust V6 Auto Trans. and 32" or 265/75R-16 MTR tires. I have experiencing power loss right after switching tires, but then gain some power after I installed SC, however, the gas mileage is terrible with SC and bigger tires, and I don't step on the gas pedal very hard, and that will avoid the tranny problem... hopefully. Also, I have been using Mobil 1 syn. oil and Mobil 1 syn auto trans oil since the truck has only 3k on it.