New_to_RX7

Hi all,

I have another questions for my newly brought 1990 RX7. My car virbrates at certain speed with and without transmission engaged. So this seems unrelated to transmission. The rear passenger side tire has uneven thread wearing (the outter edge wearing out). The wearing out portion of tire has uneven wearing pattern too.; some part worn out more than the other. This looks to me the virbration may have resulted from the rear tire jiggled.
Can someone gives suggestions what might have caused the virbration and where to look for the problem & solutions.

Icemark

tire/wheel balance.

New_to_RX7

Beside tire and wheel balance, what can possible cause this problem? and how can be diagnosis?
I have little or no knowledge about car mechanic, and I don't want to bring it to a shop without knowing anything about it. Anything that can help is appreciated.

Thanks,

SureShot

Jack up each wheel & push on it, to see if the wheel bearings are OK.
That tire may have been on the front before you got the car.

Also when you have a rear wheel off the ground, turn the tire back & forth to feel & hear any drive line backlash slack or noise.

WAYNE88N/A

If it's only at higher speeds, after checking everything else these guys said, check the ball joints....

AusTexRex

Check your struts too.

rhvix

If it is at a certain RPM, it could be in the motor/exhaust, if it is only at certain speeds, it is probably in the tires, if it is always present while moving it is probably in the drivetrain, bearings or suspension..
at least that is my experiences.

New_to_RX7

Hi everyone,

Sorry for bring up this thread again. My car's vibration problem has been fixed. I think it might be useful to tell others about what I did. I followed other's suggestions to check the wheel bearing, tire rod, engine and transmission mounts. They are all in good condition. Did a wheel alignment, they were off the spec. After the alignment, only small improvement.

Brought the car to the shop, jacked it up and checked the driveshaft by grapping the shaft and twisted it back and forth. It was found there were a lot of free play. U-joints were worn. Ordered some u-joints for replacement, but was unsucessful. New u-joints did not fit well.

Finally bought a good condition used driveshaft, put it on. Car drives smooth! All vibrations are gone!

Thank you everyone for the inputs!

Madrx7racer

ha!!! I was gonna say U-Joints....you got lucky........i found out AFTER IT BROKE....damaged my tranny too.........oy

glad it worked out in the end.

ronbros3

you may have had a bent drivshaft , i had a vibe. turned out to be bent stub axle drivers side,