The deal with the automatic transmissions is they are designed to fail. They almost never put a large enough transmission fluid cooler in front of the radiator. The transmission fluid pan is too small, you need a larger sump. Plus you almost never get a drain pug in the pan. Luckily there are aftermarket parts to correct this. 90% of A/T failures are heat related. Keep the fluid cool and change at regular intervals will cure most of the problems. Doesn't matter what truck this is...