98 gtp tranny problems???

[Cash4Cookies]

Hi im new here, and I was having trouble with a 98 Grand Prix gtp. I am driving it around to see if I want to buy it. It has almost 150,000 miles on it. I really have two problems, one is when I accelerate too fast, the whole front of the car shakes. All my friends say its the motor mounts? My second problem just started happening this morning, I went out to go get the paper, went in reverse out of the driveway and everything was fine. I put it in drive, and it doesnt go anywhere, it just revs and acts like its in neutral. I can put it in 1st gear manually and it goes, also 2nd gear works, its when I try 3rd or if I just put it in drive then it acts like neutral. Is this going to be a huge problem? Will I have to get a new transmission? Thanks!

[GTP Dad]

Yes it is going to be a huge problem and may lead to a transmission rebuild to the tune of $2400. If you haven't purchased it yet take it back and walk away. There are others out there.

Welcome to the forum!

[Cash4Cookies]

Thanks for the reply, hmmm, that sucks that its not going to be something easy. He was going to give it to me for pretty cheap, like 3000$. Well, thanks for the advice!

[97RedGPGT]

I'm having a similar problem with my '97 GT. Twice when stopped at a traffic light, pushed the gas and the engine revved, but it was like the car was in neutral. Had to shift to Park and back to Drive to get the car to go. What is wrong with the transmission? You say it will be big $$$, but does anyone know what has to be done to correct the problem? Thanks.

[richtazz]

The problem is either a shift control/TCC solenoid or pressure control solenoid. Either way, replacement involves dropping the trans out and removing the valve body and/or front pump assembly to replace. You may be able to unstick it with Trans-X or Seafoam trans treatment.

[BNaylor]

Originally Posted by 97RedGPGT

I'm having a similar problem with my '97 GT. Twice when stopped at a traffic light, pushed the gas and the engine revved, but it was like the car was in neutral. Had to shift to Park and back to Drive to get the car to go. What is wrong with the transmission? You say it will be big $$$, but does anyone know what has to be done to correct the problem? Thanks.

Other possibilities could be the transmission range switch or a deeper mechanical problem. The PCM has to be able to reference what gear postition the tranny is in before providing any shifting commands. The shift/park cable could be worn out or the range switch could have a bad contact in the drive position. Easiest to check.

In drive, shift solenoids A ( 1 -2 ) and B (3 - 4) must be energized by the PCM so the shift solenoids and/or valve body is a possibility. Mechanically, in DRIVE the following components could be acting up:

1) Input clutch
2) (1) Input sprag gear
3) Forward band
4) 1 -2 Support roller clutch

You'll probably have to take it to a tranny specialist. Plus they can scan for tranny specific DTC error codes. Most do not give a SES light either.

BTW - When was the last time the ATF and screen filter were changed and how's the ATF level?






Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.