Barry Schwartz wrote:
>
> >
> >Fellow Scions,
> > I may have inadvertently left off what could be an important
> >diagnostic syndrome when describing my latest malady. The sound,
> >not unlike that of a u-joint going out, seems much more prevalent when
> >off the gas pedal. Could the fact that the axle UJ's were going out
> >cause the drive shaft (prop shaft) UJ's to go prematurely?
> >
> >I await your diagnosis eagerly....well, not THAT eagerly...it DOES mean
> >throwing the ol' Spitfar back up on jackstands.
>
> -------------------reply
>separator----------------------------------------------
> Axle u-joints would not cause the drive-shaft u-joints to go any sooner. It
> also stands to reason that the u-jionts will make more noise when in the
> un-loaded condition, thereby alowing them to 'knock around' than when loaded
> and not able to move so freely. Thats usually why you hear them knocking
> when going around a corner, the side that gets unloaded 'knocks' (same with
> bearing noise-the unloaded side vibrates).
>
> Barry
> bschwart@pacbell.net
Interesting coincidence, my '74 Spitfire suffers the same noise when
quickly releasing the throttle, or just bad timing during a shift. I
replaced the U-joints
on the 1/2 shafts a year ago and only drove a few hundred miles since.
The prop shaft looked in good condition then too. My guess, and I
haven't got back under to confirm this, is the bushings that the
differential mounts to have seen better days. Since it's usually under
torque when driving, backing off the throttle would change the
"direction" of the force and with any play in the mount it would slap
back the other way. Well, that's a semi-educated guess for now. I'd like
to know if it turns out to be something different.
Dave (daveejay@peak.org)
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