would this be a transmission problem?

my car is in the shop right now, but i was wondering and i will have them check this out also, whenever i accelerate and the car shifts out of first gear i think, the car feels like it just went over a huge bump (but i know i diddnt), like it will jerk forward really hard, coule the tranny be slipping?

my car is in the shop right now, but i was wondering and i will have them check this out also, whenever i accelerate and the car shifts out of first gear i think, the car feels like it just went over a huge bump (but i know i diddnt), like it will jerk forward really hard, coule the tranny be slipping?


Based on the experience I have with my car.....sounds like the line pressure is going way up to me in the tranny. When the computer see's something it doesn't like going on in the tranny...it could run up the line pressure....and cause it to shift like you have a shift kit.....I don't think it is slipping. I would drop the pan and put a new filter in ASAP....you may prolong the repair.

Also.....this will really put your motor mounts and tranny mount in for a workout....

what year is your car? 97 or new I would say line pressure getting maxed out a possiblity if its a 96 or older I would say no line pressure spike cuz it is not computer controlled

If the transmission is a 4T60 or 4T60-E,(4T60=3.1,4T60-E=3100) i'd say you have no vacuum to the modulator valve, or the diaphragm in the valve itself is bad. The modulator valve is located on the front of the transmission, with a vacuum line running to it(usually steel with rubber ends)..Harsh shifting isn't going to hurt anything(unless it's severe) and actually helps the clutches and bands last longer..

what year is your car? 97 or new I would say line pressure getting maxed out a possiblity if its a 96 or older I would say no line pressure spike cuz it is not computer controlled


Good point Troy......I did not ask what year it was

I can't believe no one asked him what year and model GP he had not counting Troy.

I've worked with Mike561 so much I have it memorized. It is a '98 GTP with 4T65E-HD tranny and he probably has well over 100K miles. <-- Just a guess. :lol:

Yeah Bob....thats what I get for being a newbie...lol

Yeah Bob....thats what I get for being a newbie...lol

Just pulling your leg Ernie. :lol2: You are a great AF enthusiast. :bigthumb:

I know your messin' with me Bob.....I deserve it too!! LOL

I can't believe no one asked him what year and model GP he had not counting Troy.

I've worked with Mike561 so much I have it memorized. It is a '98 GTP with 4T65E-HD tranny and he probably has well over 100K miles. <-- Just a guess. :lol:
haha yea your definetly correct, it actually just turned 110k miles the other day. but i'll definetly mention all these things to my mechanic, should i have him change the transmission fluid too anyway?? im getting so fed up with all these problems ive had with this car, they are very beautiful car's im sure you all would agree and i love driving it, i just cant stand all these mechanical problems, if this keeps up i might just end up selling it. whoever had it before me must have beat the hell outta it. but i do thank all of you once again for helping me through all this. :banghead:

New fluid would definitely reduce the harsh shifting, by reducing the coefficient of friction..

Sorry to hear you are having so many problems. Overall a Grand Prix is a great car. I've had mine for 8 years. IMO but a lot of the used ones leave a lot to be desired, especially if it is a GTP. They get dogged by the previous owner(s). Plus you do not really know what the prior maintenance history is. You have to do what is best for you even if that includes getting rid of it and moving on.

yeah im just hoping that all these things that i get fixed will reduce more and more of the problems ive been having, but im just not sure anymore if its going to be worth it in the long run, i'd hate to have to get rid of it, its a nice car, hence why i got it of course.

I am having the same problem with my 95 grand prix se 3100. Whenever it goes to shift from 1 to 2 it hesitates then finally shifts. But when it shifts it is a pretty hard shift. I put a bottle of sea foam tranny treatment in there and it seems to lessen up the hard shift. So i plan to change the tranny fluid this weekend along with the filter. I am going to look and see if it has the modulator.

yeah im going to have my mechanic check/change the fluid and filter so HOPEFULLY that will fix things, i know transmission jobs can be VERY costly.

Yep, my car has the modulator. Looks like i know what i will be up to this weekend. How hard is it to replace the modulator?

yeah im just hoping that all these things that i get fixed will reduce more and more of the problems ive been having, but im just not sure anymore if its going to be worth it in the long run, i'd hate to have to get rid of it, its a nice car, hence why i got it of course.

Sometimes I wonder if I got the only good GP made.

The modulator is held down by one bolt, 10mm I think.

Mines going in for a pan drop and filter change at 51k when I get the time.

I experience harsh shifting periodically when I open it up every once in a while. But I have the 4T65E standard (00' GT) and if I remember right there have been issues with some of those trannies.

These are great cars if you keep them maintained. Some people just run the hell out of them, don't do the regular maintenance and get rid of them when the next fad comes out in automobiles. For instance, my car had the original fuel filter on it when I bought it in 2004 (38k).

I would take the 97-03 models over the new pregant turtles they make now under the Grand Prix name any day.

I would take the 97-03 models over the new pregant turtles they make now under the Grand Prix name any day.

:werd: You're starting to sound like KustomKid54. However, he stated a "Turtle with Braces". :lol:

With all due respect to people that bought them it is an ugly car. The more I look the more it sucks. The design of the 97 - 03 is timeless.

Oddly enough it was an 04' model that made me buy my car. It was a rental the at fault party's insurance was paying for when my Ranger was totaled. But just like you stated, as I look at them more and more they get uglier and uglier.

I'm interested (scared actually) at the possibility that GM is going to put out for its replacement in a few years. I've seen pictures of what they are supposed to base the G8 off of and it doens't impress me.

just to let everyone know that helped me out from before, i got my car back from the shop on sat. afternoon, turns out the shaking when i would push the gas down was some of the spark plugs were misfiring, and i diddnt have any front brakes left either. so i got all new plugs and wires and all is good with that now, and the tranny doesnt seem to be shifting hard, or at least not as hard anymore. i am keeping my fingers crossed that this is it. my mechanic said quote "the car was running like sh*t"

Umm... well that works too.

Glad they figured it out for you before replacing the tranny and then telling you that wasn't the problem and you needed plugs and wires.

I would still think changing the tranny fluid will help out your tranny. BUT... before you do that get a can of SeaFoam Trans Tune and add that, run the car for 5 miles and then dump the fluid and add fresh fluid. That will help flush out any gummy residue and junk that has built up in the system over time without shocking the system like a trans power flush will do.