Review on ACDelco OEM 88962315 Transfer Case Range Select Position Sensor for GM vehicles by Kip Robinson

Purchased this OEM encoder (ACDelco 88962315) to fix the "Service 4WD" message on a 2004 Z71 Suburban. (My code reader pulled out diagnostic code C0327). I followed the YouTube videos to remove the transfer case motor assembly and replace the encoder. Here are my tips: I jacked up the car using the front jacking points on the rail (greater access for under car storage). The front wheels still touched the ground. Fender removed (4 x 15mm cap screws). The transfer case motor is secured with 3 bolts - 15mm head) One next to the front propshaft propshaft. I didn't remove the front driveshaft as the screw can be accessed with a bent wrench. When the bolt came out, the bent key collided with the drive shaft. I then used the ratchet wrench until it collided with the driveshaft. I finished this screw with a regular "flat" wrench (one flat at a time) to finally loosen the screw. (Note that I was able to rotate the front driveshaft to access the bolt head - otherwise it would have been impossible to remove the bolt without removing the driveshaft.) The wiring harness was secured over the transfer case and was difficult to detach. Encoder R&R is easy with the geared motor on the table - clean the outside to keep dirt out when it's open and follow the tips in the videos. Note that only the torx screws need to be removed (the outer four 2 x T15 and 2 x T20) Mark the gears with a marker to maintain the alignment of the two gears. Also, don't lose two spacers - one for each cog. The videos I saw didn't mention this. Replacing a transfer case motor is difficult: Aligning the motor and input shaft assembly with the transfer case is critical - it only goes one way and the shafts are keyed to align properly. Apparently my transfer case input shaft moved (rotated) after removing the motor assembly. It is released by manually moving the input shaft counterclockwise about 30 degrees (until it clicks against the stop). I've attached the transfer case motor assembly without the black insulator a few times to make sure it's reproducible. Then I really installed it with the insulator and the "trick screw" (I also used blue threadlocker on the screws). After all the bolts were tightened and the wiring harness was connected, I turned the ignition on and the "wait for 4WD" message was gone and the 4WD lights on the switch seemed to be working properly. Some videos mention reprogramming the car and I didn't have to do that. All in all it took several hours. For $65.00 for encoder/print and same day delivery it was a good job. (Difficulty note: Easy enough, but I found I needed a couple of wrenches to get to the bolt behind the driveshaft.)