Westieterrier
OBS Enthusiast
My 1999 C2500 w/ 5.7 engine; 4L80E tranny; 10.5 Corporate Rear; 1-ton springs; and 155K miles that hauls a heavy Lance Camper (total GVW 8,800 lbs fully loaded) has recently developed a problem when downshifting in drive (No. 3 on selector) on steep hills at 55+ mph. The tranny seems to shift into some kind of tranny limp mode after I hit the gas to climb a steep hill.
It doesn’t do this on normal hills or on flat ground unless I hit the pedal hard to downshift and rev the engine, which I never do in normal driving. The issue really only arises when I’m driving with the Camper across the Cascade passes out here in Oregon.
After I am in this limp mode I need only turn the engine off and restart. Then all is fine again, and my OBD reader shows a Code 0131, which typically erases itself after a while unless I store the code. Sometimes the check engine light will come on when it is in this tranny limp mode, but then it turns off after stop/restart and a short drive.
I drained and flushed the tranny fluid and replaced the filter. It did not stop the problem. The tranny shifts fine otherwise and I can drive the truck normally for weeks until I have to climb a steep hill somewhere and the problem returns.
Now I know what the “E” stands for in my transmissions name! I’d like to permanently fix the issue but don’t know where to start. Any ideas greatly appreciated?
It doesn’t do this on normal hills or on flat ground unless I hit the pedal hard to downshift and rev the engine, which I never do in normal driving. The issue really only arises when I’m driving with the Camper across the Cascade passes out here in Oregon.
After I am in this limp mode I need only turn the engine off and restart. Then all is fine again, and my OBD reader shows a Code 0131, which typically erases itself after a while unless I store the code. Sometimes the check engine light will come on when it is in this tranny limp mode, but then it turns off after stop/restart and a short drive.
I drained and flushed the tranny fluid and replaced the filter. It did not stop the problem. The tranny shifts fine otherwise and I can drive the truck normally for weeks until I have to climb a steep hill somewhere and the problem returns.
Now I know what the “E” stands for in my transmissions name! I’d like to permanently fix the issue but don’t know where to start. Any ideas greatly appreciated?
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