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Hard shifts in all gears

We have a 2001 Venture with 100,000 miles. Transmission was fine until fluid was changed. About a week after fluid change it started shifting hard in all gears. When the ignition was turned off and restarted it would shift normally. This continued on and off for a few weeks. Only suggestion was a trans flush to remove a possible piece of dirt, etc. Everytime it started shifting hard, it could be corrected by restarting. It finally stopped shifting hard on its own. I haven’t found anyone with a possible diagnosis. Not my mechanic nor the Chevrolet dealer. Any suggestions would be appreciated. I am getting close to the 150,000 mile mark for another fluid change.

Trans fluids should be changed by a mechanic, not a quick lube joint. There are specific fluids for each transmission and some quickie shops use only a few “generic” fluids to save some money.

Have your transmission serviced by a mechanic, Chevy dealer, or independant transmission shop. This way you are most likely to get the proper fluid.

What caused the rough shifting 50K miles ago? Possibly it was the wrong fluid put in the transmission. Something may have caused the transmission to “forget” its shift points and it had to “relearn” them. This happens most often when the battery is disconnected.

Flushing an old trans like yours is generally not a good idea. Better to have the trans pan dropped the filter changed and refill with the proper fresh fluid. Flushes improperly done can dislodge dirt which can find a home in the transmission many tiny passages, valves, and seals and can create more problems than they solve. Avoid a flush.

How was the fluid changed? And how many miles between fluid changes?

Tester

Thank you for a quick response. My mechanic has his own shop and is very experienced. He actually did not recommend changing the fluid unless it was burnt or dirty. It still looked good with no odor. I had just purchased the car a couple of months earlier from a friend. I thought I would follow the Chevrolet recommended change cycle. I will not change it in the future unless there is a problem with the fluid.

Thanks again for your reponse,
Paul