Find the ATSG e4od rebuild manual and read through it to find all the availiable updates that were done through out its life cycle to help you pick the best version for what you want. I'm pretty sure there is a copy of them on this site in one of the older posts, give it a search. The 4R100 has all the same internal hard parts however the pump and solenoid body were designed to be controlled with a PWM signal that was used in the '99 and later PCMs. So you can use the 4R100 if you swap the necessary components back to the E4OD design or maybe you can get a 4R100 contoller from USSHIFT. The 4R100 has the cumulation of all the E4OD updated already installed, however there are some clutch packs where an extra friction and steel can be added to make them even stronger. Check with Brian's Truck Shop to find out which clutches are best to add to. Also you should upgrade the trans cooler to the 6.0 diesel trans oil cooler, on the truck chassis it's practically a bolt in component and it's nearly as large as the a/c condenser so it's very effective.