I am experiencing a transmission hard shift problem on my 1999 Pontiac Montana. Everytime it shift gear it's a similar feeling as being bumped.
The van has 45,000 miles and the transmission oil is clean and level is normal. The problem started on the highway on my way back from a very dusty road.
I have been told a solenoid that control shift points could be the problem.
Any idea? Is changing the solenoid an expensive repair?