4t65e-hd limp mode

[budgetgtp]

So I looked for a thread on this and could not find one. Recently bought a 98 gtp and the trans was slipping, so I bought a donor tranny out of the same year regal (supercharged as well) to rebuild. Just got the rebuilt tranny in yesterday. I had all new interior electrical components put in with the rebuild. I drove it about 50 miles and it was shifting good, but while I was driving the trans went into limp mode (3rd gear only). I checked the codes and got p0748, p0753, p0758, p1860. These are just about all electrical codes that would be on if the trans was not plugged in. I checked all connections and grounds and they all checked out. I also tried driving it unplugged and there was no change, leading me to believe this is an electrical issue. I checked the TCC fuse under the hood and that checked out as well. Anything that I am missing? Does anyone know if these wiring harnesses are compatible with each other, or do I need to put the stock wiring harness into the rebuilt tranny?
Thanks in advance for any answers!

 

[BillBoost37]

There is another fuse for power to the trans. I don't know which one currently, but there is.

 

[budgetgtp]

I thought so too but I can't seem to locate it. It wouldnt be an inline fuse would it?

 

[budgetgtp]

Update...car will barely move now. I put the original speed sensor back in it, took it for a test drive with no change. Went to turn around and now the car hardly moves at all. I really have to goose it to get it to go anywhere. Fluid still is at a good level and is not burnt. Anyone else have any ideas? Is it possible that they sent me the wrong shift solenoids? Im kinda stuck...

 

[budgetgtp]

Update (mainly if someone else has this problem.....) main power wire was broken INSIDE the main connector. That was repaired, but did not fix the lack of movement. Out came the trans again, tore it apart and found a broken 1-2 coast band (I believe). Put back together and runs like a champ. Thanks for all the help