JacobL
Newbie
I have a 1998 GMC 2500 pickup with 110k miles. The transmission worked fine until about a month ago.
80% of the time it shifts perfectly. But every once and a while it won't shift to 4th, the other gears shift hard, and the engine light comes on. Usually, if I shut it down for a few minutes and start it again, it will run OK again. The fluid is clean and smells fine.
I plan to get a code reader tomorrow and see what it says, but what's most likely to cause this? Speed sensors? Valve body? I'm hoping it's not the torque converter.
80% of the time it shifts perfectly. But every once and a while it won't shift to 4th, the other gears shift hard, and the engine light comes on. Usually, if I shut it down for a few minutes and start it again, it will run OK again. The fluid is clean and smells fine.
I plan to get a code reader tomorrow and see what it says, but what's most likely to cause this? Speed sensors? Valve body? I'm hoping it's not the torque converter.