Vibration During acceleration

I have a 1995 Pontiac Trans am LT1 with the automatic transmission no performance mode button.


When accelerating I have a bad vibration from 40 to like 60 mph anyone got any ideas i'm thinking maybee motor/transmission mounts. It doesn't do it if I accelerate hard or if i accellerate really softly, only if i use a medium accelration.

also trans fluid is where it should be


Also i have a oil leak it seems to be from the front and the back parts of the motor and when the car is at temp sometimes i will get smoke from the back of the engine because of it buring the oil I guess any ideas on that

Could be a bad U-Joint. Check both ends of your driveshaft to see if they're still secure. Also, it might be your tranny mounts going bad. Try getting a crow bar up beside your tranny and see if you can wiggle it back and forth. If you see your tranny moving, then your mounts are bad.

Generally vibration like that is caused by the steel unbalanced driveshaft in LT1's. There was a GM service bulletin issued in regard to it and it is very commen. A easy fix is to replace the steel unbalanced driveshaft with a Aluminum balanced driveshaft like the one's used on the LS1, a side bonus of doing this is added power to the ground cause of the aluminum shaft weighing 1/4+ less. If you need one of these let me know as I have supplied many other members with them. Also a commen vibration problem can be caused by damaged mounts but since most times that type of vibration would be felt stronger at take off than highway speeds, also U-joints would cause a clunking as you started off then as speed increased would become less noisy and produce less vibrations. Good luck to ya.

John

might also be a bad torque converter.

Well mounts were fine, talked to a guy that works at a transmission shop and he said from how I explained it, it's most likely the torque converter

also said it'd be about 400-500 to replace including labor, is that a good price?

That sounds like a good price to,

yea, thats a good price. I recently had the converter and other things replaced in my transmission. Believed a new torque converter cost, here it is, cost me jus under 300 dollars just for the part. And the installation is quite frankly a cold hard bitch. To do it, hes gonna have to take off exhaust, drive shaft, drop the transmission out, then he can get to the converter.