2002 GMC Sierra Hard, short shifting and overheating

STOGEN

MEMBER
2002 GMC SIERRA
V8
2WD
AUTOMATIC
227,124 MILES

Was diagnosed at Autozone with Transmission Pressure Switch issue. Took to Dealer, had Tran. Pressure Manifold Switch replaced and front U-Joint. One week later and 269 added miles, transmission shifted harder than normal, with fluid getting hot and gauge showing hot. Stopped it completely, let set for 5 hours and went back for it. Drove another 5 miles to home and parked it. I drove the truck for the past week and noticed some rougher than normal shifting. I don't think this was anything dealer related, thinking maybe the torque converter is going out. This is the Allison transmission and 6.6 turbo diesel 2500HD. Wanted to elaborate on the correct model. This was the first time that it has ever overheated. Thank you for your comments. While driving it home I had to stop at stop signs at every cross street for appx. 1/2 mile. Was traveling about 40 mph when the gauges notified me of the heat problem. Haven't noticed any leaking and the tran. Fluid is full on dipstick.

1 Reply

MHPAUTOS

MECHANIC
31,938 POSTS

Hi there,

Thank you for the donation,

There are a few things that I would be doing first, I would re scan and check for any further unresolved fault codes or re set codes that were just repaired, I would go to a transmission specialist and get the oil cooled checked and also get a service test and report done as for a problem like this you do need to be checking things like line pressure, shift pressures and other internal functions that will require some specialist equipment to test and monitor, transmissions are extremely complex these days, so I would be getting a specialist to do the diagnosis as second guessing this problem may end up an expensive exercise.

Mark (mhpautos)