If someone is going through T-400's they are doing something wrong. Towing overloaded and generating high heat, not running a large enough trans cooler or are not keeping up on filter and fluid changes. I've pulled many loaded miles with T-400 and never had one go bad. As routine maintenance I changed fluid and filter every spring plus I ran a large aftermarket trans cooler. One rig was a crew cab, 454, carrying an 11 1/2 ft camper pulling a heavy 4 horse trailer, 18K weight and one trip was 2 laneing it through the hills/mts of West Virginia