tranny shudder

[corey6135]

I just bought my car an 89 mgm-gs the 97 nyear old man hardly took care of it although the motor runs smooth. the shuddering occurs only when decelarating and also pick-up or accelaration is horrible. I changed the wires plugs and cap and rotor. made a little difference. any suggestions???

[fredjacksonsan]

Sounds real familiar -- is this when you let off the gas coming up to a light? Does it idle a little funny sometimes? Check back on previous posts, there are several that address this problem.

[corey6135]

Yes it does. When its cold it shifts ok but o.d. shifts in real hard practically wanting to drop the shaft. would a rebuild kit fix this? I priced one at autozone for 115.00

[fredjacksonsan]

The rebuild kit I bought didn't change anything on the 4th gear shifting, which was ok. I found that the shuddering when letting off the gas came from the idle being funny, and the car would stall at stop lights. There are a couple of posts about what was done (for my and other cars too) I'll sum up:

1) Vacuum leaks, both in the engine compartment and in the emergency brake release. The E brake thing, if you check under the steering column near the firewall, you'll see a white plastic crescent. There's a thin vacuum hose that runs through the firewall and connects there. Another thicker vacuum hose runs from there to the ebrake. It's supposed to release the brake when you put the car in gear. If you hear a hissing sound from down in that area, it's likely the white crescent.

2) Idle air valve/motor. It's found on the windshield side of the intake, mounted at a 45* angle sloping down towards the driver side. Once I replaced mine, my idle went back to normal and the shuddering when letting off the gas went away (had already fixed the vacuum leak, which was contributing). Has 2 8mm bolts and an electrical connection.

Hope this helps, if you need more info check my previous posts on the subject.

Good luck, be interested to hear if this fixes it.