Transmission Hard Shift when warmed up

[Bonneville since 1984]

I have recently purchased a 2002 SSEI. It is my sixth Bonneville and my third SSEI. The vehicle has only 97,000 miles. I have done the Intake Manifold Gaskets. The Transmission Fluid is not in the best shape and I do not know if it has ever been changed.

When the car is warmed up and everything is at temperature I will get an intermittent hard shift as my speed is going up and down. If I accelerate, there is no problem at all. The SC kicks in and the downshift works well. It is during slight changes in speed in urban traffic where the thunk will occur.

A local transmission shop tells me that a solenoid that controls shift points could be at fault. He even gave me the Code Number, which I promptly forgot. The cost for fluid change and solenoid is estimated at $1,200.00 - 1,300.00 dollars. They also "Hinted" that once the transmission is open they may have seal problems.

I am not in a position to spend the 1300 hundres dollars, let alone the cost for a "Rebuild" project. I am a mechanic. Although I do not work in the profession any more. I have changed Tranny Fluid in the past. It is a very messy job.

I have also paid to have a rebuild in a 1990 SSE. I wasn't cheap, but I kept the car for another 50,000 miles and then gave it to my son for a Graduation Present. The cost of the work was worthwhile.

Does anyone have experience with this situation? Is the solenoid an item that can be easily changed when I drop the pan to replace the fluid?

Any help or direction would be greatly appreciated.

[Bing]

Sounds like your PCS is starting to act up. It is located deep in the transmission and is accessed from the side. You have to drop the tranny or at least drop the drivers side to access the side cover and pull it all apart.
Another fix is to do a shift kit, it softens the hard shifts, it might not necessarily make them go completely away. It can be made with off the shelf parts and a couple springs from a GM dealer near you.

Here is a link that I used and followed for my shift kit.
http://www.midwest3800.com/forum/kb.php ... icle&k=187