Please help me diagnose a vibration

[guitarfish]

Hi all,

My wife's '02 Prix has 216K on it, I need 'er to last another 10-11 months (about 7K miles) before I can get a replacement car. The symptom, most noticable at 50mph and faster, is when the suspension gently glides up and down as it would on highways, there's a vibration feeling/sound as the car comes down. So if it goes up and down 3 or 4 times from a dip in the road, it's going to vibrate 3-4 times in succession.

The sound seems to be something rotating, but not smoothly. Wheel bearings are the only thing I could think of. The front wheel bearings were replaced 5K miles ago, the rear ones are original, so 216K. The tires have more than half tread left and seem fine.

Anyone have any ideas on what else I should check? As far as checking the rear bearings, all I know to do is jack it up, spin the wheel and listen for gritty sounds, as well trying to move the wheel side to side & up & down.

[gmtech1]

Have the axle shafts been replaced? If the vibration is from the front, it could be because the inner tri-pot joints are worn. The bearings travel over the worn area of the housing as the shafts travel in and out due to suspension movement.

[guitarfish]

Originally Posted by gmtech1

Have the axle shafts been replaced? If the vibration is from the front, it could be because the inner tri-pot joints are worn. The bearings travel over the worn area of the housing as the shafts travel in and out due to suspension movement.

Ya know, that makes a heck of a lot more sens than rear bearings. I think you got it buddy.

[guitarfish]

I just thought I'd check back in and say THANKS! Last weekend I changed the passenger side CV axle, and tonight I did the driver side. When I reached in to pull the driver side out of the tranny, I found out why the car was making the vibration noise - all the grease that should've been inside the boot was glopped all over the underside of the car. The metal ring on the large side of the CV boot was pretty loose, and what a mess! So I guess with grease exiting, and water & gook entering, the joint failed.

Changing the driver side was a momma, the pass side was much easier. Anyway, it's done now. I haven't taken it for a test ride yet, but I'm confident it's all quiet now.

Oh here's the best part - 3 months ago, the car passed inspection! It had subtle vibration back then. They onbviously never noticed all the grease. Duh.

Thanks guys.