4R70W VS 4R75W replacement

[joezek]

My 2003 2wd is starting to have trans problems. Just planning ahead and was thinking if it might be possible to upgrade to the 4R75W as a replacement when it does fail. I was gonna look for a used one, and rebuild it myself. The engine is stock and has 155,600 miles.

Are there any tranny experts here?
Are there different harnesses or sensors on the 75W?
Would I have to reprogram the computer?
Is the output shaft the same length and diameter?
Can I use my existing torque converter provided that I overhaul it?
Is the trans mount the same?

 

[99 Expy]

Not quite a tranny expert, but I can get ya started here. I was looking at doing this swap, but decided I'm gonna wait to do a ZF6 instead. A member on F150online did this about a year ago in his truck. For the tranny, the 4r75w and 4r75e are pretty much identical, but the 4R75E is just newer. The 4r75 cases are the same as the 4r70, so it will bolt directly in with the same dimensions and everything, and the driveshaft will remain the same. I believe the stock torque convertor will work, as well as stock mounts.

For the parts to interchange, you have to drop the valve body and replace the EPC solenoid with one from the 98-03 transmission, then he swapped the internal wiring harness from the 4r75w to the 4r75e, and swap the connector on the OSS sensor. The trannies have a different OSS count, so you will have to have a custom tune to accommodate that. I would recommend talking to Mike at 5 star tuning since that is who did his.

Like I said, I looked pretty heavily into this swap, but decided I wanted a manual instead. The swap is pretty straight forward since it all bolts in, as long as you can change the solenoid and wiring yourself. If I remember right, the EPC solenoid is like $50, so I would just buy a new one while your at it.
Hopefully this will help you out, if I think of anything else, I will add it in, and here is the link to his swap.

http://www.f150online.com/forums/transmissions/432734-2004-4r75e-2000-4r70w.html

http://www.5startuning.com/