This is my second thirdgen that does this now. Once I get to about 65-70mph the car starts to vibrate and you can see the dash shaking. I just replaced all four tires due to wear and I was hoping having 4 new BALANCED tires would solve the problem but of cource it was to no prevail. I'm guessing the front in just needs replaced, becasue I do get alot of bump steer and steering wheel vibration. Whats you'll opinion, and how common is this seeing how every third gen I've been in does this it seems like.

 

id have to wonder if there were any accidents that involved the front end before replacing it...

check the driveshaft, perhaps replace it with an aluminum one (reduced weight and less rotational speed reduce vibration at high speeds)

 

Alignment?
Balanced driveshaft?
Bent wheels?
Who balanced the tires...Wal Mart?
Bent axles?

 

No walmart just changes my oil, LOL J/K Hell no, it was a friend of mine who balanced my tires, and it had this vibration feeling before that also. It just never got any beter after the tires. I know the drive shafts are crappy in these cars but I seriously dont think thats the problem. My car has 114k on it, and my guess is it just needs a new front end. I'm thinking of ordering a polyurithane kit, but I'd be pissed if that didn't help.

There are a few other reasons I think it's my front end
1) I get a lot of bump steer
2) There is alot of vibration through the wheel while driving

Anyone out there had these problems and tried this?

 

i too have a problem with vibration above 60mph. my car already had the aluminum driveshaft, put new shock/struts, new tires, and the problem still persists. i believe it to be a rear end problem. something is wrong in there.

 

I have the same problem guys. I have replaced EVERYTHING on my car that freakin spins, among other parts. I installed new springs, struts/shocks, Pitman Arm, Idler Arm, Centerlink, changed wheels/tires, ballanced wheels/tires, new rotors, got an aluminum driveshaft (ballanced twice), and finally, just installed a whole freakin rear end out of an 80 something Camaro, and I STILL have the freakin vibration!!!! I'm going to try swapping wheels again, and I will soon put new power steering box in there along with new tie rod ends, but if that doesnt solve it, I have absolutely NO idea what it is, and I'll probably end up taking it to an expert If ANYONE has ANY info on ANYTHING that might solve this problem, please let us know. Thanks!

 

My car does this somewhat also. I was wondering if you guys have asked anything about this on the suspension board. Mine has new shocks springs struts, balanced tires and I have swaped out the rear, but that was because I wanted the posi and disk brakes. I still have the crappy driveshaft, so I just figured that that was what it was but I would like to know of other things that cause this.

Thanks

Ben

 

Well I'm happy to know I'm not the only one out there with this problem, although I'm sorry you all share it too. Have any of you ordered a front end kit that includes Control bushings, Ball Joints, outer tie rod ends, etc? There is a PST polygraphite kit ad on the back of most car crafts and Chevy High Performance magizines, I might give that a try after the holiday's.

 

I have been planing on getting that also, but my motor died so all of my money is tied up in it right now.

Thanks

Ben

 

If the vibration is caused by the driveshaft you'd be getting that vibration whenever you hit that rpm in the other gears.

I would check the wheel bearings next. The inner bearings are a pain to get to and alot of mechs will skip it and just regrease the outer bearings. Take both bearings out and clean out all the old grease and I'll bet you'll see some play in the inner bearings.
If you wait too long and drive around with worn bearings eventually you will trash the races that the bearings fit into and then you'll need to have a shop remove them and press new races in the hubs.

I just helped a friend with this same problem in his van and new bearings fixed the vibrations.

 

I have already replaced the bearings and races on my front wheels also.

Ben

 

Have any of you tried a 4 wheel alignment?

High mileage cars with an accumulation of hard runs can torque that unibody out of whack if it doesn't have some chassis stiffening modifications.

It's my guess a 4 wheel alignment might give some insight into that.

 

I believe that mine is the driveshaft, and I know that my front allignment is out of whack again. How would they realign the rear wheels on a solid axle.

Thanks

Ben

 

I don't know...but in a recent magazine (Car Craft or HiPerfChev) within the last year did the suspension on the car...might have been the Magnum TPI. Afterwards they showed the car getting the 4 wheel alignment, and said to be sure to have this type done after such drastic changes to suspension.

I'll look up the article later.

I believe any tire shop (Goodyear for example) can do this. Those alignment machines have lasers and all that.

My L98 Auto didn't shake when I first got it...but does now. The only difference in the car is worn tires on my rear and the unibody torqued enough that my ground effects are beginning to crack on my driver's side. I don't have SFC's.

Another possibility is that the tires roundness could be off enough that it causes vibrations (problem for most cars in my opinion). They fix that by lathing off some tread to have equal tread height all around the tire.

If the vibrations are onll at certain speeds I would suspect tire related. If the vibrations are constant, I would suspect something more mechanical

My .02

 

Bad or dry ball joints can cause vibrations as well

 

How about replacing the U-joint?

 

I already have new ball joints and they are greased frequently, and the driveshaft has new u-joints in it.

 

Put the rear up on jackstands and spin 'er up to where it usually vibrates. Try it both with and without the rear wheels installed. Does it still vibrate? Then the problem's in the drivetrain or rear end. If not, then the problem's in the front suspension somewhere.

Bang. 1/2 the possibilities eliminated right there.

That's how tracking down vibrations goes- you have to eliminate what is NOT causing it until you're down to one single inescapable reason.

I could throw about 10 more suggestions at you but they are worthless. You'll end up throwing parts at it for months and maybe STILL not track it down. Diagnose the problem, don't throw parts at it. This is how peoeple get sick of their cars and end up selling them.

Driveshaft vibration is totally different from tire or suspension vibrations. It's a much faster vibration- almost a low hum that shakes the entire car sorta like being in a blender. Tire/suspension vibrations you can feel every oscillation. If it's in front the wheel will usually shake back and forth in time with the vibration.

 

You can always put enough weight on a rim to balance out the tire/wheel assembly, but if the tire was produced or has worn to an out-of-round shape, you will always have a vibration at high speed.

Jack up the front end and first check the front wheel bearings for play. Then if thats OK, rotate the front tires by hand and check the runout of the tread surface. If the tread surface moves in and out by more than 2mm (0.80"), you will have a vibration.

 

I know this is an old post but has anyone gotten rid of their vibrations? I am having the same problem.

 

As suggested earlier, put the rear end up in the air, and bring it up to speed. Do this very carefully. Chock both the front wheels.
A very slight blip of the throttle will be enough to bring you to over 100mph. I was able to simply put it in gear, and let it "roll". It shifted through a few gears, and the rear began shaking so badly, the answer was pretty obvious.
Do it first with the tires on it. If it shakes, take the rims and tires off, and try it again. No shake, it's the tires/rims. If it still shakes with no rims/tires, it's either the axle or driveshaft. As Damon said earlier, the driveshaft is a much higher frequency vibration, like a big sander stuck on the roof of the car.

 

So you said it was obvious. Was it your wheels? Was one warped? I'll try it on my car this weekend.

 

I have the same problem with my 83z28.... I was thinking it mainly only does it when im slowing the car down.... I was wondering if its a problem with the rear end itself, because the car drives straight and everything, and you can definetly hear alot of chatter in the rear, no idea how many actual miles are on the car, so I was thinking about putting a new gear set in the rear?

 

I was referring to the fact that it began shaking so badly, it was pretty obvious it was "something" to do with the rear. After removing the rims and tires, and getting no shake, it turned out to be a tire out of balance. The guy at the shop I used said it was 4.5 ounces out. (but it had weights...)

@TheTech91RS:
Sounds more like rotors to me, since it's only during braking.