GM 4WD Transfer Case Encoder Motor 600-899, 2007-2018

This is the 4WD transfer case encoder motor (also called the transfer case shift motor or shift actuator) for 2007-2018 GM full-size trucks and SUVs with the push-button electronic Autotrac / Active Transfer Case system. It replaces OE numbers 19258696, 23369032, 84109212 and 84718571, and cross-references to Dorman 600-899. The motor bolts to the rear of the transfer case, and the encoder ring inside it is what tells the transfer case control module where the range fork actually is.

The failure is easy to recognize on the drive: you press 4HI or 4LO and the dash light blinks and then goes back to 2HI, the truck stays in two-wheel drive, or it hangs between ranges and the service 4WD light comes on. Common stored codes are C0327 (encoder circuit), C0306, C0374 and C0710. Sometimes the truck will shift into 4WD but refuse to come back out. That is the encoder contacts inside the motor wearing out - the motor still spins, but the module no longer gets a clean position signal, so it aborts the shift and defaults to 2HI. Cleaning connectors and re-flashing the module will not fix a worn encoder; the motor has to come off.

Replacement is a driveway job on jack stands. Disconnect the battery, unplug the two connectors at the motor, remove the three 13mm nuts holding the motor to the transfer case, and pull the old unit straight off the range selector shaft. Line the new motor up with the shaft flats before seating it - do not force it - then torque the nuts down evenly, reconnect, and cycle the switch through 2HI, 4HI, N and 4LO with the engine running and the truck rolling slowly to let the module relearn the encoder positions. Clear any stored C-codes afterward.

Fitment: Chevrolet Silverado 1500 2007-2018, Silverado 2500/2500HD 2007-2013, Suburban 1500 2007-2014, Suburban 2014-2018, Suburban 3500HD 2016-2017, Tahoe 2007-2018, Avalanche 2007-2013, Colorado 2015-2016, Cheyenne 2007-2017. GMC Sierra 1500 2007-2018, Sierra 2500HD 2007-2013, Yukon 2007-2018, Yukon XL 1500 2007-2014, Yukon XL 2500 2007-2013, Yukon XL 2015-2018, Canyon 2015-2018. Cadillac Escalade ESV 2016-2018.