Transmission Fluid Leak, Erratic Shifting on GMC Vandura 2500

Problem Description and Possible Solution

On the 4L80-E Transmission (Diesel and 7.4L gas engine), Transmission fluid may leak through the electrical connector on the side of the transmission, damaging the wire harness and causing the transmission to shift erratically. Our technicians tell us there are updated shift solenoids, an internal  transmission harness, and a connector pigtail available to correct this fault.

Problem Data
RepairPal Verified
Average mileage: 108,000 (108,000–108,000)
3 model years affected: 1991, 1992, 1993
5 people reported this problem
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Shifts hard when goes from first to second gear then runs the their shifts smoothly.not fixed yet