Because I have some serious vibration at 80MPH I went to a driveshaft shop because I was sure the problem was from that source. He comfirmed it after test drive.

The guy told me that they don't replace u-joints and I need to buy a new or rebuilt driveshaft: cost: $366.00 plus shipping plus installation for a total of $477.00.

I am perplex because these u-joints are available for replacement.

Opinions please.

I forgot to sat it is a 72 240z.

go to another shop!

$10.64 ea @ www.rockauto.com

$14.04 ea @ Motorsport

$12.95 ea @ Victoria British

$?????? @ your local NAPA or auto part store.

if you don't know how to replace them, you could pay for labor.

hope this helps,

bart

I agree with Bart....go to a real driveline shop. Any reputable driveline shop will have no problems repairing your driveshaft. Shoot, for less than the price they quoted you, I had a complete new driveshaft made up...better balanced and stronger that the stock unit. Again, find a good shop. In the Las Vegas area I would think this would be no problem, especially with all the off-road events that take place there! Good luck and let us know how it turns out.

I have received two other quotations from driveline shops. One is $325.00 installed, another one is $400.00.

I found another shop that could replace both u-joints for $109.00.

The car has never been abused and has now 90K but I am wondering what are the chances the internals of the driveshaft could be damaged.

Motorsport sells a new driveshaft for $225.00 plus $15.00 S&H.

Before you do anything you might want to check out the following url:

http://www.powertrainindustries.com/catalogs.htm

webdawg1

Thank you WEBDAWG1 for your suggestion.

They sell $255.50 including shipping.

Guys (especially Richard1)

Please let me know what sort of success you've had in eliminating the 80mph vibrations.

My 72Z also has that problem, although the vibrations are from about 50-70mph.

I replaced the U-joints on my left and right half-shafts, which both felt a bit "notchy" when I removed them.

But I still have the vibration!

I guess my next move is the central drive-shaft? But what can actually go wrong with the drive-shaft to cause that vibration???

IThe car has never been abused and has now 90K but I am wondering what are the chances the internals of the driveshaft could be damaged.

There are NO INTERNALS to a drive shaft. It has a splined yoke, two sets of U-joints, the shaft itself, and the yoke that attaches to the diff. That's all.

If the U-joints are bad you replace them (you've been given prices for the parts & labor shouldn't be much)

If the driveshaft is bent beyond repair or otherwise destroyed, you can find one in a junkyard (and replace it's U-joints), or get another new one, but I wouldn't spend anymore than $250 under any circumstances. The quote of $110 for new U-joints installed sounds like the best deal to me.

Guys (especially Richard1)I guess my next move is the central drive-shaft? But what can actually go wrong with the drive-shaft to cause that vibration???

Aside from what's already been discussed (u-joints), the only other things that could cause the vibration would be a damaged shaft (essentially a piece of pipe), mud or debris stuck to it, or the paint slipping to one side causing it to be unbalanced.

MOYEST,

I have owned a 69 510 back in 1972-77 and my girlfriend back then (now my wife) a 70 240z.

I remember very well that a half shaft u-joint going bad has not a so serious vibration and the first driveline guy I met was quite knowledgeable about the Z problems.

The kind of vibration I have at high speed is worse than when you sit in one of these electric massage chairs plus the rattling of metal noise. If you understand what I mean, it is pretty scarry. You have the feeling that the transmission and all the driveline is in decomposition but in same time you feel that it comes from the driveshaft tunnel. You slow down and the vibration is still there until you are driving around 30MPH. You can drive up to 70 MPH and it will not reappears

This morning I went up to more than 90MPH before this vibration suddenly appeared.

My car is fully original and none of the U joints have ever been replaced. They are checked at regular maintenance and they are sound.

Again. I am wondering if it is not more the internal components of the driveshaft that are the problem instead ot the u-joints.

Please, some comments from the Z mechanic gurus.

There are NO INTERNALS to a drive shaft!!!!!!!!!!!!!!!!!!!!!