I recently swapped my 4r70 due to it going out at 290,000 miles I've owned since new and I'll have to say I can't complain.... first major issue I've had and its been far from babied...the original failure was it felt like a extreme stall converter from take off lol....dead stop Itd rev to 2000 rpms before Itd pull.... once it did it was fine. It came out of no where and I limped it home and immediately dropped trans and prepared for swap. I found a 97 4r70 and after asking around was convinced with a few changes....speed sensor and linkage module swap I'd be fine.....so after that I installed and first crank up engine was in limp mode and 3 codes for shifter solenoids and tcc were showing.... replaced all 3 with new OEM parts still same....read a couple threads and figured out another never mentioned difference was the internal wiring harness was different....97 has actual wires and 01 has plastic circuit board type harness....so I swapped main plug harness and all modules over from 01 to 97 everything seems perfect match.... cranked up engine no longer in limp mode just won't shift..now has multiple codes and od light still flashing P0713 0740 0743 0750 0753 0755 0758 p1000...... really wishing I'd just had original rebuilt lol but now I'm intrigued to find the solution....and also I've checked harness from under hood to transmission for breaks chaffing etc any advice would be appreciated thanks!!!

 

It sounds like the power feed from underhood fusebox fuse F23 isn't making it into the transmission. Start by checking that fuse.

While the 97 and the 01 4R70W connectors are the same, the vehicle side of the harnesses are different. Did you take the complete circuit details into account in your swap?