I have a 2001 Pontiac Grand Prix with 91,000 miles on it. I find that after I have driven it for a while and it is warmed up, the transmission jerks when it shifts. It doesn’t appear to have problems shifting, it just shifts really hard. This is an intermittent problem and doesn’t seem to happen when the car is cold.
When was the last service done (fluid and filter change)?
It’s possible dirt or perhaps metal filings float around and plug up a valve in the tranny after the fluid gets hot.
I did have it serviced in November and that is when this problem started.
This is a computer controled transmission. If the computer senses that the transmission oil is too hot or a clutch element is slipping, it will command full line pressure shifts. Is the ‘OD’ light blinking or the check engine light ‘on’ when this happens. After a restart, the transmission will shift regularily until the fault happens again. Have the transmission computer scanned for diagnostic codes by a transmission technician. Any resultant codes will steer him/her toward a better diagnosis of the problem and the solution.
Same thing happens to mine. haven’t noticed it for a month now. I also have 91,000 miles. I took it to a shop and they said computer controlled transmission nothing you can do to fix it fluid was good. It did spit a code the tech said the tranny was at it’s max setting for wear.