basically the biggest reason for having auto trannies go bad, is overheating. im guessing this is sitting behind a big block, and it has alot of weight to push around, so heat will be there. Just run the stock cooler into an aftermarket, like a B&M 24kGVW bar and plate cooler, and then back to the tranny, and you should be just fine as far as overheating the fluid goes. you may or may not find benefit from a shift kit, like a transgo kit, to firm up your shifts. the added vein pressures will reduce slipping of the clutch bands and also reduce heat aswell.