Mudwheelin wrote:The service light comes on only sometimes when I start it up. It also comes on when I try to put it in 4hi.
I had the same problem, it was very intermittent on mine, not saying It's the same, but in awd mine would crow hop, and sometimes not engage the front, the axle locked up, but the tc wasn't sending power to the front. I ended up replacing the encoder motor sensor, and that fixed the service light.
The easiest way I found to test it is to pull the motor off and pull the sensor out, and hook it up to a meter, It's essentially a potentiometer, I didn't measure the new one, but from the old os, it should change resistance when the ring is turned. My old one stayed put at 6.9k ohms, and open at 7 and 9 oclock with the pins facing down. I would suspect that to be the cause, as the 4x4 test flow chart leads you to believe It's all ok, and saying your front axle doesn't stay disconnected. Another way without pulling the motor is to connect it to a tech 2 and command the motor to specific states and see what the sensor says, but that's likely to cost some.
I ordered the sensor from rockauto, It's an ac delco part, part # 89059276.
