U0102 Check Engine Light When 4x4 is set to Auto

[netsec]

I had the 4x4 on for the first time this year since Gene Harvey Chevrolet in American Fork rebuilt the transmission. The tech had left all of the cross member mounts finger tight and my fear is he left something unplugged or damaged a sensor or wire harness when replacing it. I slid under it this morning to look and could only find that one of the bolts in the bell housing was missing. Anyone here have this code? The 4x4 appeared to be working fine, however I got the CEL and a service transmission warning which has since disappeared. I sear I have had this truck in the shop more than I have had it in my garage.

 

[netsec]

So the dealer says it's the TCCM or TCSCM (same thing) They say it takes about 2 minutes after start before it starts sending data to the system. They say the new one would be $350 + $80 to install/program. Anyone have this before? Would cleaning the connectors help? Will it damage the truck if I wait until after Christmas to fix this? Where is the tccm located? Still in the passenger kick panel?