Help!

My car has developed a vibration at about 45+mph.

I notice it more when I accelerate, but I guess even when I take my foot off the gass it's still there a bit.

Opinions so far include the drive shaft being out of balance, or the diff and gearbox not lining up true.

I dunno!?

I've heard horror stories of Z suspension or drive shafts collapsing at speed because people ignore these problems. I don't want that to happen!

I also get a metalic "click"/"clunk" changing into 3rd, 4th or 5th gear (but not 2nd).

So, I wonder whether the spline between drive shaft and diff is worn out?

Any advice re: drive shafts/vibrations/diffs???

P.S: the vibration is NOT from wheel balancing - I checked the most obvious thing first.:stupid:

First thing I would check is the U-joints, diff mounts, diff itself and perhaps the stub axle bearings as a last resort.

Could also be a transmission center bearing on the main shaft, but you wouldn't hear the clunking on shifts but a more constant whine.

is it just vibration or is there any clunking noise to it too.. if your hearing a clunking noise id suspect the u joints on the drive shaft.. but if its kist a vibration.. check your suspension.. your wheels if all the lug nuts are on tight.. jack it up and see if your wheel bearings are still good.. or bring it to a alignment shop to see if its your wheels...

My front wheels are perfectly balanced but I get a vibration at aprox. 45 mph. Turns out to be the soft rubber mounts on my steering rack (or something in that area) roughly saying that the rack is worn out and the whole front end shakes cause of it.

Just throwing that out there as a possability.

Dave

I had a vibration that came in about 80km [45mph].

Had us all perplexed for a few months.

It turned out that one of the rims had gone off centre, ie the holes had worn bigger.

Solved the problem with a brand new set of rims and matching tyres.

Hey MOYEST,

That brings up an interesting point that I was gonna bring up earlier but had to run,

Have you considered putting a different set of tires on just for the hell of it, ya never know.

It worked for me once, its a cheap and easy diagnostic tool (err.. tools)

Dave

Well, in response to all of the above:

The vibration doesn't come through the steering wheel as much as it comes through from behind the seats (and through them?). I also can hear the vibrations behind me (no smart remarks please!!).

Tyres are fine.

That suggests it must be U-joints or an unbalanced drive shaft?? Not sure.

Any other suggestions? I would have thought it was quite "common" - I've driven other Z's that develop clunks or vibrations, and thought it might be a common weakness?

Have you rotated the rims?

Since you sound like you are fairly certain it isn't a wheel/tire issue. It does sound like it could be U-joints, the diff itself, stub axle bearings, or perhaps something as simple as a dragging brake shoe?

I'd check the U-joints first, then start with the brakes, check them over completely, then go with the diff possibility last.

Then it is most definetly something going on in the rear of the car. It could be many things as most suggested.

The first and easiest to check is the tire balance and make sure the tires themselves arent out of round. Another thing is wheel bearings, brakes hanging dragging, u joints, drive axle, diff, diff bushings tranny bushings, rear control arm bushings worn and pushing the wheels out.

Do you notice any tire wear that you hadnt before?

sounds crazy but have you had any work done on the back of the car in the last 6 months or so , if so check the area serviced , there are alot of parts that could come lose if someone didn't do it correctly , had that happen to me but I would bet on u-joints , good luck:geek: