JohannB

I am getting a vibration at freeway speeds on my '90 N/A 2+2. I suspect the drive shaft. The car has 109,000 miles on it. Has anyone out there done work on this? If so, how difficult is the job? Anyone know the approximate cost to repair?

I do most of my own repairs and would like to know opinions on whether to do it myself or take it to a shop.

Any help is greatly appreciated.

Thanks,
Johann B.

91zxtt

is the vibration in 5th gear at approximately 2500 RPM's? Does the vibration increase under heavier load, such as when going up a slight incline? I have the same issue with mine. I suspect it's the driveshaft. I have a 1 piece driveshaft sitting in the garage. I just haven't had the time to change it out. I've been told it is not a difficult job, but I can't tell you 1st hand. Check out www.z1motorsports.com. They sell a real nice 1-piece steel driveshaft. It's more efficient than the stock 2 piece one, and is less expensive than a new factory driveshaft.

JohannB

Thanks for your suggestions. It is noticeable in top gear. (I have an automatic) It doesn't seem to be affected by load... only road speed. I even tried putting it in neautral at about 65 MPH to see if it made a change but it didn't affect it. It is almost a buzz at 65-70 MPH.

According to my manual, it could be the driveshaft runout, the center bearing, or the U-joints. It looks like it will be a bitch to do since they buried the drive shaft with the exhaust pipes.

I will check on the one piece shaft... especially if it's cheaper than the factory 2 piece one.

Thanks,
Johann B.

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91zxtt

Changing out the driveshaft involves removing the mid-pipes and the exhaust pipes behind the cat. Remove a few more bolts after that and it should drop right out. Not all that bad of a job. I have a 5 speed, so the symptoms can be different. My vibration goes away completely when I'm in neutral or when I let off of the gas pedal. How recently did you have the tires balanced and the alignment checked? That's another possibility. It's less expensive too. It could also be your differential bushings (that's a bitch).

JohannB

I think it's the drive shaft. I have had similar problems with other cars in the past and the symptoms seem the same. If your vibration changes or disappears when you let off the gas or go to neutral, it may be a U-joint. I had an old car when I was a kid which did the same thing.

I don't think it's the tires because they usually produce a heavier and lower frequency vibration. And, it doesn't seem to be felt throught the steering wheel. I do think the bushings need to be re-done too though.

I always say, if it's got **** or wheels, it's gonna cause you problems.

Thanks,
Johann B

Riz Z Speed

The changing out of the driveshaft isn't particularly difficult. The process is exactly like 91 described it. Just make sure you don't drop the driveshaft on your head. It's heavy.
Z1 is the place to go for a driveshaft. Their prices are good especially compared to oem. Besides a one piece will last longer, provide better reliablity, and free up more power with less rotational mass as opposed to the stock unit.

JohannB

Thanks for your input on the output. (sorry about that) I don't understand why they put a 2 piece shaft on them in the first place. I guess it's those damn engineers... they love to make things complicated.

Thanks,
Johann B.

MetalTear17

I have a similar vibration starting about 50mph, i think its a tire because it seems to be coming from the passager side front, I hope its not the driveshaft...

JohannB

I don't think mine is a tire... I've had tires out of balance before, and I've also had driveshafts out of balance, and it feels like the drive shaft. It's almost a buzz, rather than a shake like a tire makes. I don't feel it in the steering wheel as much as I feel it all over.

The Z drive shaft is known to be flawed. Thanks to another poster, I even found out that there's a replacement shaft which is 1 piece to help alleviate this problem.

Thanks,
Johann B.