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93atlsc
10-01-2008, 10:07 PM
My car has a very hard vibration. It appears to be coming from the rear mostly, but I could be wrong. Its been doing it for a while, I thought my rear tires needed balancing cause it only did it at high speeds. It is doing it now at 30 mph, harder than ever. It does it in od and d. Any help is appreciated.

Duffy Floyd
10-01-2008, 10:10 PM
Have you checked your wheel bearings lately? Sure the lugnuts on the wheels are tight? Differential bushing front and rear condition?

frdlvr30
10-01-2008, 10:22 PM
Driveshaft companion flange bolts and u-joints??

KMT
10-01-2008, 10:35 PM
Feel it in the steering wheel or seat of the pants?

93atlsc
10-02-2008, 09:23 AM
I feel it in the seat of the pants mostly. It vibrates so hard that i feel it in the steering wheel a little also, but i think it just because its so intense. The lugnuts are good. I dont think its the wheel bearings, one side was replaced and its not making that roaring sound. Im not sure about differential bushings, companion flange bolts or u joints. I've never touched any of them. When i punch it, it doesn't have that torque like it used too. Specially at speeds above 50mph. If it's the drive shaft, how far can i drive it before I need a wrecker.

SCarSC
10-02-2008, 09:30 AM
mine was doing something similar, turned out it was the drive shaft connection to the pumpkin, 4 bolts, think it is 13 or 12 mm. anyways i tightened them up and the vibration went away

XR7 Dave
10-02-2008, 09:31 AM
Highly suspect drive shaft u-joint flange bolts or a bad CV joint. The frequency of the vibration will tell you which. Axles vibrate at the same speed as a tire imbalance, driveshaft vibrates at about 3x that speed.

Slysc
10-02-2008, 09:44 AM
If the frequency of the vibration corresponds to the frequency (rpm) of wheel rotation, check the lug nuts, wheel bearings and halfshafts.

If the frequency of the vibration corresponds to about 3 times the rpm of the wheel, then check the u-joint, then the yoke bolts, or pinion bearing.

93atlsc
10-02-2008, 09:48 AM
The faster I drive the worse it gets. I would say 3x rpm.

KMT
10-02-2008, 09:50 AM
>I feel it in the seat of the pants mostly. The faster I drive the worse it gets.

Driveline related is my bet - u-joints and/or bent shaft. Ouch...

93atlsc
10-02-2008, 10:45 AM
So more than likely its not the transmission?

KMT
10-02-2008, 11:28 AM
...they, grind, squeal, whine, hum, chatter, smell, balk, pop out of gear, refuse to go into/out of gear, leak, grenade, and yes, vibrate - but not so much to the degree you've described.

I've seen input shafts cause fairly severe vibrations, but those cases were related to clutch/flywheel/bellhousing issues that exhibited a host of additional symptoms.

You can't do much but speculate at this point - seems time to start getting up close and personal with the running gear.

Have a shop check it, or DIY by getting the rear wheels securely off the ground, sitting at the same angle as when loaded. Have an assistant run it thru the gears while you do the inspection underneath. The inherent dangers should be obvious, but if you don't feel safe/comfortable doing it, take it to a shop.

93atlsc
10-02-2008, 11:31 AM
The car is a 93 automatic.

KMT
10-02-2008, 11:43 AM
>The car is a 93 automatic.

Check the rear housing on the trans for cracks/breaks. Check the fluid in the differential as well. As bad as you indicate it is, it should be fairly evident once the running gear is inspected closely.

the-big-e
10-02-2008, 02:35 PM
Check yout tires.....

You might have a broken belt in one of your tires.....

93atlsc
10-02-2008, 04:56 PM
Car is fixed! 1 bolt missing and 3 bolts loose on the yoke. I replaced the missing bolt and tightened the others. Car is driving the smoothest it has in 4 years. Thanks for the help guys!

KMT
10-02-2008, 05:06 PM
>1 bolt missing and 3 bolts loose on the yoke.

Good job - keep an eye on it just in case. Thanks for the update.

the-big-e
10-02-2008, 05:16 PM
I had that happen to my 92.....

When I bought it, I never got to drive it over 45 MPH.....

When I finally got to do the underside inspection, two bolts were missing and another one was just about ready to fall out.....:eek:

frdlvr30
10-02-2008, 10:37 PM
Thats why companion flange bolts come from the factory installed with loc-tite!!!