The 3.7 uses the NAG1 transmission. The TCM is a separate item from the PCM. Don't know where it is on the WK, but on my Hemi LX, with the NAG1, it's under the dash by the steering column. Did you keep the original PCM? If so, you can either keep it as a spare, or try to sell it on Ebay or on one of these forums. Be aware that the U0101 code means communication has been lost to the TCM. First thing to do is to find it and check all the connections to it. I'd unplug, inspect, clean and reinstall. Disconnect the battery before you do this though. One other lesson probably learned here is to not to take it to the dealer, except as a last resort.....especially if it's not under warranty. IMO, come to the forums first. So many dealers are just parts replacers and don't really know these vehicles as well as the folks that drive and repair them without dealer help. I know that every time I've reluctantly (and rarely) taken mine to the dealer, I've had to tell them what to do. Good luck, and let us know what you come up with.