2001 Grand Prix GT trany Problem

Hi gyres i need some good advice on what to do about this problem. Two years ago i was driving my car and i noticed that my tranny was shifting really hard and a whining noise started to come from the tranny.
I stopped the car and shut it of and turned it on again. it ran fine. It ran fine for another month or two. then same thing happened again one day when i was driving from work again, I realized that there was something wrong and took the car to get it checked out. They determined that a pressure solenoid needed to be replaced. I replaced a solenoid and the car ran fine for about a year A year later same problem occurred again
i went back to the same person he suggested to rebuild a tranny. He told me to drive the car until it dies. i kept driving the car and surprisingly the problem did not come back again until couple of days ago. Can someone give me an advice on what should i do. This hard shifting only happens when i drive the car at least for an hour and it is pretty warm and also as soon as it starts i am hearing a vhining noise from the tranny.

The whining sound and harsh shifting is due to high line pressure probably caused by an internal tranny problem. Since the PSC was changed out at one time your tranny person is probably correct that a rebuild may be the final solution. I know of a few cases where tranny additives such as Sea Foam or Lubegard may help. You have nothing to lose at this point. Sea Foam will help free up sticky solenoids or cure minor valve body problems. Lubegard will help condition the ATF fluid and help reduce temperatures.

If it has not been done, have the tranny shop run a scan with a trans capable scanner to see if any codes are stored. Certain codes will trigger high line pressure.

Can you tell me where i will be able to get Sea Foam or Lubegard.
thank you

Can you tell me where i will be able to get Sea Foam or Lubegard.
thank you

Sea Foam is normally available at NAPA. Lubegard at auto parts stores like Pep Boys and at AAMCO transmission shops. I haven't seen it at Autozone. Both cost under $10.

Just add the stuff after tranny has warmed up and engine running. Watch the ATF level because you could go over but a little over the mark will not hurt. Lubegard is around 8 ounces. Sea Foam may be 16 ounces but use only 8 ounces initially. It may take a while to see any noticeable results but take the car through various driving conditions including acceleration and manually operating the gearshift through the gears. Good luck!