Transmission? Hope NOT

:banghead: I have a very serious problem. I bought this 2000 Grand Prix SE (automatic transmission) from from Pat Peck, and it run very good. About 2 months later, the car would jerk from time to time when shifting to 3rd gear. The jerking got worse until it jerked in all the gears before 4th. The next problem started about a month after the jerking. The transmission would "over rev". It would do this when switching to 2nd. Now it will do this in 1s,2nd,and 3rd.
Do I need to have my transmission rebuilt or could it be something simple like a vacuum hose or something? Any help would be appreciated.

:banghead: I have a very serious problem. I bought this 2000 Grand Prix SE (automatic transmission) from from Pat Peck, and it run very good. About 2 months later, the car would jerk from time to time when shifting to 3rd gear. The jerking got worse until it jerked in all the gears before 4th. The next problem started about a month after the jerking. The transmission would "over rev". It would do this when switching to 2nd. Now it will do this in 1s,2nd,and 3rd.
Do I need to have my transmission rebuilt or could it be something simple like a vacuum hose or something? Any help would be appreciated.



i dont think it would be a vaccume line...the reults from a vacume line falling off are instant. like the slipping of all gears would have occured all at once not over a period of time. pull the dispstick on the trans fluid look at the color make sure its red...smell it..it shuld have a sweet smell. if it smells burnt youll know. also you might wanna just drop the pan (trans pan) and loook at the inside of the pan for any metal shavings take the filter down look up inside look for any sniney metal particle...basicaly looking for internal damage.

:banghead: I have a very serious problem. I bought this 2000 Grand Prix SE (automatic transmission) from from Pat Peck, and it run very good. About 2 months later, the car would jerk from time to time when shifting to 3rd gear. The jerking got worse until it jerked in all the gears before 4th. The next problem started about a month after the jerking. The transmission would "over rev". It would do this when switching to 2nd. Now it will do this in 1s,2nd,and 3rd.
Do I need to have my transmission rebuilt or could it be something simple like a vacuum hose or something? Any help would be appreciated.
if it is a 4t60/65 that problem is caused by the
Hydraulic clutch push piston seal. They usually roll over on the shaft or crack and then will not have enough pressure to lock the clutch quicky. it usually worse when cold. It also can be caused by a bad channel plate gasket. Needs rebuilding...sorry

This model Grand Prix has a 4T65E.

Best thing to do is have it scanned with a trans. capable scan tool and see if there are any stored DTCs. Possible it might show pressure control (PCS), TCC or other slippage codes many of which do do turn on a SES/CEL light.

Also, how many miles on are your car?

it has a 3.1 liter engine and has 120,000 miles on it

i have the same shifting problem but it only happens when the engine is hot. not too hot but hot from the 30 minute drive home. i have noticed though, the shifting issue goes away for the remainder of the commute if i shut the car off for approximately a minute or so. again, this is just a temporary fix. any suggestions or advice is greatly appreciated

FNG :icon16:

i have the same shifting problem but it only happens when the engine is hot. not too hot but hot from the 30 minute drive home. i have noticed though, the shifting issue goes away for the remainder of the commute if i shut the car off for approximately a minute or so. again, this is just a temporary fix. any suggestions or advice is greatly appreciated

FNG :icon16:

What shifting problem....harsh shifts or what?

And welcome to AF.

2000 3.1 grand prix se, ~135,000mi - sorry, posted that then realized i could've put in more information.

Thanks for the welcome.

hard shifting, i mean it shakes the car and feels like the trans is going to fall out. if i don't shut the car off, temporary fix, in the next 10 mins or so the service engine soon light comes on.

2000 3.1 grand prix se, ~135,000mi - sorry, posted that then realized i could've put in more information.

Thanks for the welcome.

hard shifting, i mean it shakes the car and feels like the trans is going to fall out. if i don't shut the car off, temporary fix, in the next 10 mins or so the service engine soon light comes on.

The best thing to do is get the car scanned since the SES light does come on. It has to be a tranny capable type scanner or one that will read out GM extended codes like P18XX. From your symptoms you may have a bad PCS solenoid. A DTC code of P1811 will most likely confirm that.

When was the last tranny service - ATF and screen filter?

i had the trans fluid changed ~1yr ago, no shavings found and rather clean fluid removed.

i talked to a co-worker and he said to try an additive called "lube gard", it's in a red bottle and i found it at NAPA. it did lessen the hard shifting but it wasn't a complete fix.

i talked to a co-worker and he said to try an additive called "lube gard", it's in a red bottle and i found it at NAPA. it did lessen the hard shifting but it wasn't a complete fix.

A better process is to dump 16 oz of Seafoam tranny additive and run for several hundred miles. Then do a pan drop consisting of screen filter and ATF change. Then add 8 oz of the Lubegard. If that doesn't help then it is tranny fix time.

Like Bob said earler both of you guys need to get to a shop for a code check.