Chevrolet Suburban 4WD Archives - Transmission Digest
Don’t Overlook the Basics

Our carry-out customer was working with a 1999 Chevrolet Suburban 4WD equipped with a 4L60-E transmission. Their technician was able to re-create a slip/flare condition on the 2-3 shift. The fluid was full but a little burnt. A quick hookup of the scan tool revealed no codes existing in the system. Pressure gauges were attached for testing and indicated around 75 psi at idle, and 125 psi at the half throttle position.

4L60-E: 4×4 Low Range Only After Overhaul

Once you are aware that the wire harnesses can be connected incorrectly, it is easy to look back at the problem. When the transfer-case motor-encoder plug is connected to the oxygen sensor, it will short, blowing the fuse; and when the oxygen-sensor plug is connected to the motor-encoder, it shifts the transfer case to 4×4 low range..