Took her to the dealer for a service 4x4 dash message, had been throwing it for a month by the time I got it in, scanned and got back the following codes:

C0327 Encoder Circuit Malfunction
C0379 Front Axle Malfunction
C0550 ECU Performance
B0790 Transfer Case Neutral Indicator Circuit Malfunction
B2725 Active Transfer Case Mode Switch Circuit Malfunction
U1000 C2 datalink malfunction
U1301 C2 datalink high

The stealer performed a miraculous technique passed down from generations of freaking ancient tribal medicine men called a "software update," which for some reason they thought was worth $400 to me. I hate living in a town with only one GM dealer. I know the 2725 code is the switch, but I wasn't going to pay them to do that, and I know sometimes a switch can throw an 0327 and an 0790 so they may or may not be related. Of course, the dash message came up again on my way home. I also understand that the 0550 is an ECBM-related code, and I vaguely remember some threads on this subject but not exactly where they were or what they were about.

I have already disassembled the encoder motor and replaced the sensor, about two years ago-ish, and I'd hate to think that's bad again. I had the pump rub hole a little over a year ago, had an awful time getting it fixed at a local shop and have suspected that something wasn't quite right with the repair.

But, geez, that's a lot of codes! Any more ideas about what might be going on?