Transfer case replacement woes

[grovey]

I have a 02  GMC sierra 1500 and  I've had a vibration/noise under my truck since summer.  Long story short after replacing the rear, I believe we've narrowed it down to the  push button transfer case. I felt it was binding up the few times I've used the 4wd since buying the truck last yr.  My mech  replaced the case with a used one I found with fairly low miles.  After putting it in  he  had no dash lights, and only low gear in the trans.  I google it, and found a post with a procedure  of how  pushing certain  dash buttons etc to (sych ) everything. He said  his scanner told him that too? 

Anyhow  after trying everything from  other harnesses, swapping the sensors from my old case in the replacement case, trying another replacement case, and even tried putting my original back in and still the same result.  I had a ABS  light since I bought the truck that he scanned as being the ABS speed sensor in my front pass side.  He replaced that and the ABS light was still on, but the scanner didn't  read a code.  He now wants to try a ABS control module next.   Reason being...  (back story)  I found out my brake lines were rigged up when  another one blew a month ago .  There's a chance it was ran out of fluid while trying to get to the garage then, and lord knows the details on the other two bursting.