[x300] XJR purrs but not in a good way

With a bit of luck you guys can help me with a strange noise I’m hearing on
my XJR.

Hmmm. How to describe it? If you use your tongue against the roof of your
mouth to make the sound of a purring cat, that’s pretty close. Just add a
slightly metallic or gear-like tone and that’s it.

It is road speed sensitive, starting at 30 mph and loudest at about 50 mph.
After that other noise pretty well masks it. Engine speed, engine load,
swerving left or right, gear selection, on throttle or coasting, brakes
applied or released …no difference in the noise. Even coasting with the
engine off the noise remains the same. It is positively from the rear of the
car, possibly louder on the right.

A couple weeks ago I was poking about and was a bit shocked at the amount of
free play in the right rear wheel if wiggled from 12:00 and 6:00 o’clock.
New hub bearings to care of the slop but did nothing for the noise…which,
of course, I was hoping for.

I am suspecting a diff problem but the steadiness of the noise suggests
otherwise, I think.

Any memories being jogged out there? Any clever ideas? I need could use
thought starters before I pull the propshaft or take other crazy exploratory
steps.

Center bearing perhaps?

Cheers
Doug Dwyer
Longview Washington USA
1995 XJR

In reply to a message from Doug Dwyer sent Sat 12 Sep 2009:

I think you could be on the right track with the propshaft centre
bearing,is there any vibration at all?
My old xjr6 suffered from a simmilar problem,which turned out to be
the centre bearing,however I also recall a slight vibration under
acceleration(which had been the worn rubber bearing support).
The input(pinion) bearing in the diff may well be suspect,Im pretty
sure this is easily replaced,although having never done that one
before I could be wrong!
Hopefully others will chime in with some more ideas,I would like to
find out about the diff bearings myself anyway so fingers crossed.–
1998 xjr Black.
aberdeenshire, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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I think you could be on the right track with the propshaft centre
bearing,is there any vibration at all?

Yes. I’ve had a slight and peculiar vibration for some time. Peculiar in
that it really isn’t consistant in severity or occurence

My old xjr6 suffered from a simmilar problem,which turned out to be
the centre bearing,however I also recall a slight vibration under
acceleration(which had been the worn rubber bearing support).
The input(pinion) bearing in the diff may well be suspect,

I’ve suspected that as well but talked myslef out of it, as I would expect
the noise to change going from on-throttle to off-throttle. But ya never
know. And, the pinion seal has develeoped a leak, too. Maybe it’s being
beaten up? I’ll take another look at that end of things.

Thanks for the input :slight_smile:

Cheers
Doug Dwyer
Longview Washington USA
1995 XJRFrom: “mad4jags” william.walker71@btinternet.com

In reply to a message from Doug Dwyer sent Sat 12 Sep 2009:

Hello Doug,

From your description you could be in the early stages of
the problem I recently solved - differential output shaft
bearings. You might want to look at these threads
(hopefully I’ve corralled them properly):

http://forums.jag-lovers.org/av.php?1247913k13
http://forums.jag-lovers.org/av.php?1227222k85

My first suggestion would be to run the car in gear with the
rear wheels off the ground, and see what obtains.

Feel free to email directly if you have questions.

Sincerely,

John–
The original message included these comments:

With a bit of luck you guys can help me with a strange noise I’m hearing on
my XJR.
Hmmm. How to describe it? If you use your tongue against the roof of your
mouth to make the sound of a purring cat, that’s pretty close. Just add a
slightly metallic or gear-like tone and that’s it.
It is road speed sensitive, starting at 30 mph and loudest at about 50 mph.
After that other noise pretty well masks it. Engine speed, engine load,
swerving left or right, gear selection, on throttle or coasting, brakes
applied or released …no difference in the noise. Even coasting with the
engine off the noise remains the same. It is positively from the rear of the
car, possibly louder on the right.


John Harwood 1969 E-Type FHC, 1997 XJR6
Lafayette, IN, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php

John, thanks for taking the time to reply. Yes, my noise does seem very
similar to what you described in your earlier posts. I’ll add output
bearings to my list of things to look harder at, so to speak

Cheers
Doug Dwyer
Longview Washington USA
1995 XJRFrom: “jshjag” jharwood@purdue.edu

From your description you could be in the early stages of
the problem I recently solved - differential output shaft
bearings. You might want to look at these threads
(hopefully I’ve corralled them properly):

http://forums.jag-lovers.org/av.php?1247913k13
http://forums.jag-lovers.org/av.php?1227222k85