If the TCM is what the nag ring & plug connect to inside the transmission, then absolutely the dealer could have messed it up during the repair. There is a picture somewhere on this forum of the broken electrical connectors that resulted from a plug being twisted as it was being inserted in the ring. When I did my leak repair a month ago I was very cautious when putting the plug back in. Putting it back in was not an easy thing to do, and I can see how a dealer mechanic in a hurry might have botched that part up.

Update: Picture is in this thread....

https://www.crossfireforum.org/forum...a-daaaa-4.html