ACDelco GM Original Equipment 88962315 Transfer Case Range Select Position Sensor

Fixed my red light error on my 4x4 selector switch on my 2004 Avalanche.Encoder motor cost over $100. This was actually very easy to replace and super cheap compared to the alternative.Had it on my truck since 2021 and still works great!

My transfer case has a mind of its own. I would part it at night in 2wd then start the truck the next day and would be in 4low or something like that. I installed this sensor and problem solved!

This fits my 2005 Silverado and is located inside the 4WD shift motor. Easy install once the motor is removed and the entire repair took less than an hour. Remove the skid plate, remove the front drive shaft, unbolt and unplug the shift motor. Remove 2 screws to open the shift motor, mark both gears with a marker to ensure proper alignment during re-assembly, unplug and remove encoder ring. Replace with new encoder and put it all back together. No more issues with the transfer case and now it shifts right every time.

Bought this OEM encoder (ACDelco 88962315) to fix the "Service 4WD" message on a 2004 Z71 Suburban. (My code reader pulled diagnostic code C0327). I followed the You Tube videos to remove the transfer case motor assembly and replace the encoder. Here's my tips: I supported the car on jack stands on the front lifting points on the rail (Increased access for laying under vehicle) Front wheels were still contacting the ground. Removed skid plate (4 x bolts - 15 mm head). The transfer case motor is attached with 3 x bolts - 15mm head) One is next to the front drive shaft U-Joint. I didn't remove the front drive shaft since its possible to get to the bolt with an offset wrench. As the bolt comes out, the offset wrench clashed with the drive shaft. I then used a ratchet wrench until it clashed with the drive shaft. I finished this bolt with a regular "flat" wrench (one flat at a time) to finally get the bolt undone. (Note that I could rotate the front prop shaft for access to the bolt head - without that it would have been impossible to get the bolt undone without taking off the drive shaft.) The wiring harness was pinned above the transfer case and was difficult to get undone. R&R of the encoder is simple with the transfer motor on the bench - clean the outside to stop dirt getting on the inside when its opened up and follow the tips on the videos. Note that only for Torx screws need to be removed (the four outer ones) 2 x T15 and 2 x T20) Mark the gears with a sharpie to preserve the alignment of the two gears. Also - don't lose the two shims - one one each gear. The videos I saw didn't mention those. Replacement of the transfer case motor is tricky: Alignment of motor assembly and input shaft to transfer case is critical - it only goes one way and the shafts are keyed to make it line up properly. Apparently my transfer case input shaft moved (rotated) after removal of the motor assembly. Solved by moving the input shaft by hand counter clockwise about 30 degrees (until it clicked against a stop). I attached the transfer case motor assembly a couple of times without the black isolator to make sure it was repeatable. Then did it for real with the isolator and "tricky bolt" installed (I also used blue thread locker on the bolts). After the bolts were all tightened and harness hooked up I switched on the ignition and the "Service 4WD" message was gone and the 4WD lights on the switch appeared to function properly. Some videos mention reprogramming the vehicle and I did not need to do that. This took a few hours overall. At $65.00 for the encoder / seal and same day delivery it was a job well done. (Note regarding difficulty: Reasonably straightforward but I found I needed multiple wrenches to get at the bolt behind the drive shaft.)

2005 Tahoe Z71. This resolved my issues with random issues with my 4 wheel drive. The first symptom occurred while driving down the road in 2-wheel drive and it slipped into neutral. I pulled over and shifted through all of the gears with no change. I was fairly certain that a transmission doesn't act like that when it goes unless it fell out of the vehicle. That helped me to narrow it down to the transfer case. I noticed the light next to the 2-wheel button was off so I pushed the Auto button and could feel the transfer case engage. I put it in drive and away I went. Periodically I would try to switch it back to 2-wheel and it would always slip back into neutral after a mile or so. I kept it in Auto for a few months and then started to notice that it would randomly engage the 4-wheel drive while on the pavement, yikes! Not wanting to destroy my front wheel drive, I learned that I could set it to 2-wheel and then crawl under the vehicle and completely remove the transfer shifting unit, which this device is inside (BTW, no need to remove the driveline to get it out but it takes a bit of twisting and turning to get it out, it's very tight). You lose the ability to change the transfer case setting unless you manually adjust it with a wrench underneath but it now won't be shifted unintentionally. These transfer cases are basically the same as they were 20 years ago but they have just replaced the stick on the floor with a motor and some electronics to do the manual work and coincidently, those electronics are the culprit for the majority of issues on these vehicles.Once you have the shifting unit (I don't know what it is called) off the transfer case, it is fairly easy to replace the sensor. This sensor tells the computer what gear it is in and then the computer turns the motor as needed to select the correct gear. When this sensor starts to burn out, it sends incorrect signals to the computer, which then starts to move the motor around to find the correct position and that leads to the random transfer case behavior. Your symptoms may be different. From reading online forums, it appears that this sensor is the problem 60% of the time and the switch on your dash accounts for about another 35% of transfer case problems; your mechanic doesn't want you to know that. I took apart the shifting unit on my dining table, swapped out the sensor, and put it all back together while watching the game. I don't remember anything difficult or tedious about the process. I re-installed it about one year ago and no issues since.

Had all the symptoms and codes installed this Sensor no go luckily I also bought the hole unit just in case I almost destroyed my transfer case never start truck and take it out of neutral when the transfer case is in neutral from N to drive !!!! with out confirming you are in 2H . don't be stupid like me lucky for me I pulled it out of drive before I did any permanent damage slight grinding . the new one was plug and play the transfer case was already in neutral but read 2H when I park it ?