I have a 2000 Pontiac Grand Prix SE with the 3100 engine in it. I just recently bought it and it runs great all except for every now and then, it will shift sort of hard, not extremely hard though. I, unlike those I've read here, cannot hear any problems or the tranny when it does it. And i can shut the car off for a and start it back up when its a little cooler and it wont do this. I believe it maybe be leaking tranny fluid through some seals, but ANY recommendations or definite diagnosis would be greatful. I do have a TCS button, and i believe that it does it when i push the TCS off and then back on. My fluid levels seem to be ok and this doesn't happen often at all....maybe ONCE a month. Do you recommend a fluid change or flush? What do you recommend? Thanks

It might be normal for an a shift every once and awhile to be a little off. My mom's car does the same thing every once and awhile. Might want to drop the pan and change the fluid and filter to to be on the safe side though.

Greatly appreciated advice :-D. Any idea what that costs to do in real life? I'm thinkin no more than 20 bucks.Is that anywhere near? Thanks

Probably closer to 50.

Any other thoughts on this problem?

It's just routine maintenance so it cant be too much. But closer to 50 would be my guess.

Tranny fluid, and a filter. Call your local autoparts store to get prices. I'm guessing fluid and filter alone are going to be $50.

To have someone else do it will prolly be closer to $100.

guiltyox, you described what I've been experiencing for quite some time (6mo+) in my GP SE. There are two reasons: Pressure Control Solenoid is bad or, as you guessed, seals. If you have someone fix it, it's going to cost you. I have a spare car, so I'm not too worried if it pukes. However, I also have eventual dreams of doing a L67 swap, so I'm in no hurry to have a rebuild.

Edit: Filter is about $12, and Castrol Dexron III is around $35 for 7 quarts.

I had my 2002 Se for two years and mine shifts a lil hard but its not really noisy, but I also have over 125,000 miles on mine but it still runs good. Maybe just like everyone else just change the fluid and filter, thats what I did back in february of 2005 and it has not left me on the side of the road yet.( )