4r70 to an e40d in an 03
 

ok, my grandparents have an 03 e250 that the tranny has began to slip. I have found a wrecked 00' e350 that has the same engine (5.4) that still has low miles, the only problem is that the doner has an E4od rather than the 4r70 like the 03' has. Is there a big enough difference between the two to prevent an interchange? bolt pattern, driveshaft, etc. are no problem, but what about electronics? im not sure if they use a seperate tranny module, if it would take reprogramming, or even if the wiring would match up.

any technical advise would be appreciated.

The wiring will not match up, the driveshafts won't match, and the electronics won't match. This would be a big job to do. I suggest looking harder for another 4R70W or rebuild the one you have.