Hello. I have an 89 pontiac grand prix with a 3.1L V6 engine. I recently had the transmission gasket, fluid and filter changed and now the transmission is slipping a little. The transmission slips real bad when i make left turns and just revs real high in the middle of the turn. The car has also seemed to have lost a little of its accelerating power and am wondering if a bad spark plug could be causing this. Any help would be greatly appreciated.

Um...no...no way in he double L is a spark plug causing it. Sounds like they messed up your transmission good. Did they do a flush on it? Because they shouldn't have if it is a high mileage file. Flushing it only messes it up.

How many quarts of fluid did they put in? Because it is recommended that you fill the 4T60 automatic transmission FOUR quarts over full. It keeps everything well lubricated. :D That's the way I run my 90 LE, and that is the way MANY TGP owners run their cars.

The car has about 141,000 miles on it and I believe the mechanics did flush the transmission. I checked the fluid level and it was only about half full. So is there anyway to reverse the damage?

Um..did you check the fluid correctly? Checking transmission fluid is different than checking oil ;) If you did check it correctly..and it's only half full, then you need to add more fluid and check it again.

If there is some damage done to it, the only way to repair it is to replace or rebuild it.

I bet its your LSD is goin out. Mine did the samething and a few weeks later I blew my tranny, put three holes the size of baseballs in the end cap, was not pretty. Mine got to be so bad I could be doin 20 and gun it and hit red line before it would check and squell like a banshee as the tranny finally caught.

Also another reason why it might be the LSD is when I first bought my car I was driving it to the insurance company and as I was turning it just revved and finaly caught, I took it back cuz I had just bought it like 20 minutes ago and they said to just change the fluid, I flipped out and was like no you will fix it and it turned out to be a bad LSD.

What exactly is the LSD? and do you know about how much it would be to have replaced?

LSD is the Limited Slip Differential (sp?) its what distrubutes the power to your wheels to make them go I beleive, you could go buy one from zzp for $500 and put it in yourself its pretty easy or pay like 150 for someone else to put it in, I am not to sure on how much one would be new or from a junkyard. best thing is take it to a shop or dealership and have them check it out before you go spending tons of money for something it may not even be.

hold the thought on the zzp LSD i just noticed you have a 89 so it may not work cuz your tranny is different then my 97. I bet though a new LSD is expensive though so I would just go to a junkyard if thats the case that you LSD is goin

I've always heard bad things happening after flushing the tranny on cars with high mileage.

Not sure about on the 89 trans, but on the 97+ you can check the differential by pulling the speed sensor and seeing if there are any peices of metal on it.

The speed sensor is magnetic, it senses the differential spinning and calculates the speed. On my 98 I had snapped the roll pin on the pinion shaft and the shaft was moving in and out of the carrier, thus scrapping on the outer case. The shavings made it into the valve bodies and I stuck a valve. If I would have pulled the sensor I could have seen all the shaving stuck to it.

New Differential was $400 from GM. It's not a "LSD" until you buy either the INtense unit or Cya Racing unit

Good Luck,

Tim

Thanks for the help and suggestions. I will probably take the car to a transmission shop and have it checked out, hopefully they won't be as incompetent as the mechanics who flushed the transmission .

To clarify things....89s DID NOT have LSDs. They had normal differentials. There is an LSD available for the 4T60 though. It can be found here: http://www.geocities.com/pontiacjeff/EPlsd1.html

I will be putting one in my 1990 TGP next spring.