I have a 2000 Buick Regal with 100,000 miles. When it is cold it drives fine but when it gets warmed up like on a long drive it will shift hard when changing gears. Do you have any ideas on what the problem is?
It could be that the computer has picked up a fault somewhere and is commanding full line pressure from the pressure control solenoid inside the transmission. Have the computer scanned for codes and post back with them if there are any. Has the check engine light come on at all, especially when the harsh shifting is ocurring??
No there is no light. It will run fine. Then after about 40 miles of driving it will start to shift hard. I will have it checked for codes.