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Intermittant transmission problem

Occasionally, when I start my 1994 Chevy pickup (205K+ miles), the check engine light will remain on and the automatic transmission will shift with a clunk and will shift much more slowly into the next gear. This generally only happens when I’ve driven the car, then stopped for 5 minutes or less then started it again.

The first time this happened, I shut off the car and popped the hood to check the transmission fluid level. The dipstick was very hard to remove but after removing it I remembered it needed to be checked while the truck was running. When I started it again, the check engine light was off and the transmission was acting normally! My mechanic looked at the truck but couldn’t get the problem to repeat. This still happens intermittantly (once or twice a week) but the problem always goes away if I shut off the engine and pull out the transmission fluid dipstick. In these circumstances, the dipstick is always hard to remove, although under normal conditions it is not. I suspect some kind of vacuum is being developed.

Any suggestions as to where to look for the source of my problem?


Have the stored computer fault codes retrieved … they may tell you why the transmission is acting-up.

I agree, have it scanned first. If nothing shows up then drive it until the harsh shifting shows up again then without shutting off the engine, scan it and see if a code shows up then.

Post back with the code/s and we can go from there. To be honest with you 205k on a 4L60E transmission is a lot of miles and if an overhaul is indicated, I wouldnt feel too bad. You got a lot of miles out of it.