I have a newer body style 99 silverado with a automatic transfer case that is not locking into four wheel drive. The front axle locks in because I placed it in 4WD and put the front end up in the air and checked. But when I put the rear axle in the air, while in 4WD and motor running in gear, the transfer case does not turn the front drive shaft. I can hear the encoder motor inside the transfer case running when I push the 4WD and 2WD selector buttons so I assume it is shifting from 2WD to 4WD high to 4WD low to 4WD auto, etc. but the transfer case doesn't lock up. I don't know if the encoder motor is what shifts the vehicle into low gear when you push the 4WD low button, but it does go into low when you select 4WD low. It is easy to tell that it is going into low because it just creeps along. Would a front or rear speed sensor cause the transfer case not to lock into
4WD? Whatever makes the transfer case lock in or regulates it locking in, is not working. I do not have a 4WD/AWD service indicator light on. And all the indicator lights on the 4WD and 2WD selector buttons say the trasfer case is shifting from 2wd high to 4wd high to 4wd low, etc. My only indication that things are not right is that the transfer case is not turn the front axle. Any ideas? Thank you!- posted
20 years ago