Re: [alfa] driveshaft vibrations/looseness

["Dean W. Cains" <dwc@xxxxxx>]

Hi Richard:

I believe what you're describing isn't all that unusual, and several older 
GT's I've seen over the years have been updated to the later style center 
support bearing, including a '68 GTV I owned more than 20 years ago. Here's 
a link to a Wes Ingram article on the subject:

http://www.geocities.com/motorcity/downs/3837/centsup.html

Running the engine to spin the driveshaft with the car raised is OK, but 
only if you've got the jackstands under the suspension.  If you let the 
rear axle hang freely, you will get all sorts of nasty noises that don't 
necessarily indicate a problem.  Also, it's tough to feel loose u-joints 
with the driveshaft installed, and the free play you're feeling in the 
differential is probably OK, too.  You might also have an issue with the 
transmission mount, but I believe one of the UK vendors now sells a proper 
reproduction.  Maybe Alfaholics or Highwood Motors?

Regards,

Dean
Lutz, FL
'74 & '87 Spider Veloce's


At 08:23 PM 7/11/2004, you wrote:

> Date: Sun, 11 Jul 2004 15:59:34 -0700 (PDT)
> From: Richard Lane <srlane@domain.elided>
> Subject: [alfa] driveshaft vibrations/looseness
>
> I have a 1967 GTV with some driveshaft issues.
>
> A year ago I removed and went through and fixed everything on my driveshaft -
> front-nose bushing, center bearing, center (old-type rubbery) support, pinion
> seal (car has a 1980 rear axle so LSD), checked the UJs and they were 
> perfect -
> but still now i seem to have two types of vibration.
>
> One is the sort of high-speed hum style. This I think I will attempt to cure
> with the hose-clamp method, right now it's not bothering me that much 
> because I
> also have...
>
> the second vibration, most noticeable when pulling up to a stop. A real
> low-speed shudder/judder tooth-rattler, this one needs to go first.
>
> So, I jacked all 4 wheels off the ground (w/stands), took the rear wheels off
> and ran the engine in gear. Not much to notice in 2nd gear, but at about
> 12-1500rpm in 4th gear there is a really nasty clanging/banging/rattle 
> from the
> driveshaft, so loud it was impossible to tell whether it was from front or
> rear.
>
> This then, I think, is the same as my low speed vibration, made worse by the
> lack of wheels and forward inertia to dampen the vibration. Feeling the
> driveshaft while still on the car it all feels pretty tight, UJs and the
> splined joint all feel good. But, what doesn't feel good is the play in the
> shaft as it goes into the diff. In other words, if I apply the brakes so that
> the hubs don't turn, there is about 5-10 degrees of rotaional play when 
> turning
> the shaft before it binds in either direction.
>
> So, it feels like a lot and is the only thing (I think) that could cause that
> rattle. So how much play should there be there? - is it adjustable? - by the
> home mechanic? Do you think that could cause my lo-speed-vibes?
>
> Thanks for any advice,
>
> - -Richard Lane
> San Jose, CA
> 1967 GTV
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