User_name
T.B.I Guy
2000 GMC c3500 cclb dual rear wheels. 107,000 miles. 4l80e/7.4L.
When I start the truck and for about the first 10 minutes of driving, the truck shifts smooth as butter, through all four forward speeds.
Then out of nowhere, the truck will kick its self out of overdrive and shift hard, staying in third and not going back into overdrive until I cycle the key.
When I cycle the key, it’ll do the same thing, hot or cold. Shifts like butter then locks out overdrive and I assume it also commands max line pressure which is why my shifts get hard.
-trans is full and clean
-trans does not seem to be overheating
-engine operating temp hangs out around 190-200*f
-shift linkage seems good
-no codes, pending or stored
I’m thinking this has to be a tcc solenoid issue, wiring issue, or the brake light switch. Truck was very well taken care of until the guy bought a diesel and it has sat since 2018.
I just want some input to point me in the right direction before I jump on it this Friday.
Thanks to all who respond.
When I start the truck and for about the first 10 minutes of driving, the truck shifts smooth as butter, through all four forward speeds.
Then out of nowhere, the truck will kick its self out of overdrive and shift hard, staying in third and not going back into overdrive until I cycle the key.
When I cycle the key, it’ll do the same thing, hot or cold. Shifts like butter then locks out overdrive and I assume it also commands max line pressure which is why my shifts get hard.
-trans is full and clean
-trans does not seem to be overheating
-engine operating temp hangs out around 190-200*f
-shift linkage seems good
-no codes, pending or stored
I’m thinking this has to be a tcc solenoid issue, wiring issue, or the brake light switch. Truck was very well taken care of until the guy bought a diesel and it has sat since 2018.
I just want some input to point me in the right direction before I jump on it this Friday.
Thanks to all who respond.