Service 4WD light on Check engine light on
Service 4WD light on, can’t shift into 4WD, 4WD shift doesn’t work, transfer case motor doesn’t work on Avalanche, Silverado, Suburban, Tahoe, Ram, Sierra, Yukon, Check engine light on
Cardone, a leading manufacturer of rebuilt transfer case motors has issued a service bulletin advising shops of a reason why a brand new Cardone motor may not work properly. In fact, the same problem may be the root cause of the factory transfer case motor not working. Apparently Chevrolet, GMC, and Dodge ground both their transfer case motors and their PCMs to the frame rail towards the back of the driver’s side front wheel well. Since this location is exposed to road salt, the connection may corrode to the point of producing faulty check engine lights and malfunctioning transfer case motors. Before condemning the transfer case motor, users should disassemble the ground connections and clean away all the corrosion. Then coat the connection with dielectric grease to retard future corrosion and reassemble. If the transfer case motor now works, you’ve found the problem. If not, replace the motor.
© 2012 Rick Muscoplat