The tail housing and output shaft would be different. Other than that, I believe the two ZF5HP24's are the same. You can not simply swap in the 740i transmission unless you plan to leave off the transfer case and make a custom driveshaft so that you can run 2wd. That would be more effort than simply rebuilding the transmission. Likely, it's a new o-ring, thrust bearing, and shim that is easy to access once you have the front cover off. Full transmission rebuild might not be necessary.

I did the full rebuild last year. It was "fun" and a learning experience. Find the service manual for the ZF5HP24 on the internet. Make sure you order the right parts. I ordered a ZF5HP24A filter on accident.