1991 GMC 2500 Pickup Repair and Maintenance

A guide to problems, costs, maintenance and repair for your 1991 GMC 2500 Pickup

1991 GMC 2500 Pickup Problems

Transmission Fluid Leak, Erratic Shifting

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.

Quick-connect fittings for heater hoses may leak engine coolant

The quick-connect fittings for the heater hoses tend to leak engine coolant. This problem commonly occurs because the metal housing has become brittle, which can break and cause leaks.

Alternator May Fail and Cause Noise and Dead Battery

The alternator may fail causing the battery to go dead, or an abnormal noise may develop. The dash warning light may or may not illuminate. A failed alternator will require replacement.

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1991 GMC 2500 Pickup Questions

When towing a trailer with a car do I put it in 3rd gear or in overdrive? (1 answer)

I think the question is pretty self expanitory...thank you

Blower stopped (1 answer)

I have checked the fuses inside relays and maxi fuse outside and they are all good. I get no power to the switch but I can jumper to the motor and it does spin.

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