Hard shifting after short tow/unhooked battery

[JPaul]

So last night I picked up a popup tent trailer from a friend and towed it back to my house with the Alpha, it was less than a mile. Everything was fine and I didn't notice any issues. After that as part of my work to get everything ready for the Moab trip I unhooked the battery terminals and then put them back on. Didn't start or drive the truck after that until I left for work this morning. When I started down the road everything seemed ok, but then I noticed my speedometer dropped down to 0 while I was going about 20 and then came back up, then for a few seconds or so the traction control light came on and then I got a traction control error, then that cleared. After that my 1-2 shift became really hard and kept shifting hard the whole way to work (which with how many dang traffic lights I have to stop at really sucked).

I checked codes and got a U0073 which indicates a communication failure in one of the CAN bus's. Apparently there is also a TSB on the Hummers and several other vehicles that address potential sources of the probelm, mostly dealing with pins backing out of the transmission wiring harness connector at the transmission, and chafing/shorting of various other wires related to it.

This really sucks having this happen the day I'm supposed to be leaving for Moab, but hopefully I can get this all sorted out in time. If anyone else has experienced this and fixed it I'd love to know, but I'm going to be working on this in hopefully the next hour or so.

 

[JPaul]

So driving home from work it was just fine, no hard shifts or anything.

Im wondering if the problem was caused by my Ultragauge being plugged in through the battery disconnect. I noticed that it was stuck on the scanning screen (the one that comes up when you first plug it in) so I disconnected it when I got to work and plugged it back in, after that it quickly connected to the computer and booted up all the way. It's possible it was causing interference on the bus while the other modules were trying to link back up with each other or something like that.

Hopefully that's all it was, since I really dont want to either get stuck or something during this trip.

Sent from my SM-N950U using Tapatalk