Weird noise from rear of XJ
 

Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises, and
they are really too intermittent to pin down. Thought you guys might have
some ideas. It only started recently and seems to happen the most frequent
when it is really cold out and it hasn't had much time to warm up. It
doesn't happen every time under these circumstances, but that seems to be
when it happens the most.

Basically, it is a loud.. noise.. upon acceleration, and only when starting
from a standstill and only when giving it a little more gas than usual.
Almost like a rattle, but deeper, coming from the rear. I thought it might
be the exhaust pipe rattle against my shackle (I have 2" extended shackles
and one touches the exhaust pipe -- yes, yes I need to cut it..). That
doesn't make sense, though, because it would happen all the time...

Anyhow, could this be the rear u-joint? How would I check it? Could it be
something in the diff (doubtful)? I don't know, but the noise is pretty
loud. Loud enough to really get our attention today.

Thanks guys.

Eric

Re: Weird noise from rear of XJ
 

Does it do it under acceleration in reverse. I had the same thing going on in
my 2000 xj and couldnt nail it down. Changed the tranny mount and fixed it. I
also have a small lift on my jeep and I think this might have something to do
with the cheap tranny mounts breaking. I bought a polyurethane Daystar mount
from Mesa4x4.com and it actually rides better than it ever did. One problem
with the poly mounts though is they do have a little bit of a vibration stopped
at a stoplight at idle, if you can live with that they are great. Let me know
what you think, the problem with your stock tranny mount is you won't be able
to tell it is cracked even when you take it out, I think the rubber just gets
stretched and worn out. Hope this helps, please respond to my comment!
Trevor

Re: Weird noise from rear of XJ
 

Does it do it under acceleration in reverse. I had the same thing going on in
my 2000 xj and couldnt nail it down. Changed the tranny mount and fixed it. I
also have a small lift on my jeep and I think this might have something to do
with the cheap tranny mounts breaking. I bought a polyurethane Daystar mount
from Mesa4x4.com and it actually rides better than it ever did. One problem
with the poly mounts though is they do have a little bit of a vibration stopped
at a stoplight at idle, if you can live with that they are great. Let me know
what you think, the problem with your stock tranny mount is you won't be able
to tell it is cracked even when you take it out, I think the rubber just gets
stretched and worn out. Hope this helps, please respond to my comment!
Trevor

Re: Weird noise from rear of XJ
 

Does it do it under acceleration in reverse. I had the same thing going on in
my 2000 xj and couldnt nail it down. Changed the tranny mount and fixed it. I
also have a small lift on my jeep and I think this might have something to do
with the cheap tranny mounts breaking. I bought a polyurethane Daystar mount
from Mesa4x4.com and it actually rides better than it ever did. One problem
with the poly mounts though is they do have a little bit of a vibration stopped
at a stoplight at idle, if you can live with that they are great. Let me know
what you think, the problem with your stock tranny mount is you won't be able
to tell it is cracked even when you take it out, I think the rubber just gets
stretched and worn out. Hope this helps, please respond to my comment!
Trevor

Re: Weird noise from rear of XJ
 

If there is water in your differential you might hear the gears chewing
up the ice from a cold start. If you suspect this, put a pan or bucket
under your diff and remove the cover to let the oil out. While you're in
there, check the gears for any chips or missing teeth. If you can, lift
one or both of the rear tires so you can rotate the gears to inspect.
Use a quality synthetic gear oil with a good cold-temp viscosity when
you refill.

Steve
90 XJ

Eric wrote:
> Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises, and
> they are really too intermittent to pin down. Thought you guys might have
> some ideas. It only started recently and seems to happen the most frequent
> when it is really cold out and it hasn't had much time to warm up. It
> doesn't happen every time under these circumstances, but that seems to be
> when it happens the most.
>
> Basically, it is a loud.. noise.. upon acceleration, and only when starting
> from a standstill and only when giving it a little more gas than usual.
> Almost like a rattle, but deeper, coming from the rear. I thought it might
> be the exhaust pipe rattle against my shackle (I have 2" extended shackles
> and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> doesn't make sense, though, because it would happen all the time...
>
> Anyhow, could this be the rear u-joint? How would I check it? Could it be
> something in the diff (doubtful)? I don't know, but the noise is pretty
> loud. Loud enough to really get our attention today.
>
> Thanks guys.
>
> Eric
>
>

Re: Weird noise from rear of XJ
 

If there is water in your differential you might hear the gears chewing
up the ice from a cold start. If you suspect this, put a pan or bucket
under your diff and remove the cover to let the oil out. While you're in
there, check the gears for any chips or missing teeth. If you can, lift
one or both of the rear tires so you can rotate the gears to inspect.
Use a quality synthetic gear oil with a good cold-temp viscosity when
you refill.

Steve
90 XJ

Eric wrote:
> Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises, and
> they are really too intermittent to pin down. Thought you guys might have
> some ideas. It only started recently and seems to happen the most frequent
> when it is really cold out and it hasn't had much time to warm up. It
> doesn't happen every time under these circumstances, but that seems to be
> when it happens the most.
>
> Basically, it is a loud.. noise.. upon acceleration, and only when starting
> from a standstill and only when giving it a little more gas than usual.
> Almost like a rattle, but deeper, coming from the rear. I thought it might
> be the exhaust pipe rattle against my shackle (I have 2" extended shackles
> and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> doesn't make sense, though, because it would happen all the time...
>
> Anyhow, could this be the rear u-joint? How would I check it? Could it be
> something in the diff (doubtful)? I don't know, but the noise is pretty
> loud. Loud enough to really get our attention today.
>
> Thanks guys.
>
> Eric
>
>

Re: Weird noise from rear of XJ
 

If there is water in your differential you might hear the gears chewing
up the ice from a cold start. If you suspect this, put a pan or bucket
under your diff and remove the cover to let the oil out. While you're in
there, check the gears for any chips or missing teeth. If you can, lift
one or both of the rear tires so you can rotate the gears to inspect.
Use a quality synthetic gear oil with a good cold-temp viscosity when
you refill.

Steve
90 XJ

Eric wrote:
> Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises, and
> they are really too intermittent to pin down. Thought you guys might have
> some ideas. It only started recently and seems to happen the most frequent
> when it is really cold out and it hasn't had much time to warm up. It
> doesn't happen every time under these circumstances, but that seems to be
> when it happens the most.
>
> Basically, it is a loud.. noise.. upon acceleration, and only when starting
> from a standstill and only when giving it a little more gas than usual.
> Almost like a rattle, but deeper, coming from the rear. I thought it might
> be the exhaust pipe rattle against my shackle (I have 2" extended shackles
> and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> doesn't make sense, though, because it would happen all the time...
>
> Anyhow, could this be the rear u-joint? How would I check it? Could it be
> something in the diff (doubtful)? I don't know, but the noise is pretty
> loud. Loud enough to really get our attention today.
>
> Thanks guys.
>
> Eric
>
>

Re: Weird noise from rear of XJ
 

But would the diff make loud enough noises to be heard/felt in the cabin?

Eric
"Steve" <xjlfter@bogus.com> wrote in message
news:1jSOb.67875$IF6.1612418@ursa-nb00s0.nbnet.nb.ca...
> If there is water in your differential you might hear the gears chewing
> up the ice from a cold start. If you suspect this, put a pan or bucket
> under your diff and remove the cover to let the oil out. While you're in
> there, check the gears for any chips or missing teeth. If you can, lift
> one or both of the rear tires so you can rotate the gears to inspect.
> Use a quality synthetic gear oil with a good cold-temp viscosity when
> you refill.
>
> Steve
> 90 XJ
>
> Eric wrote:
> > Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises,
and
> > they are really too intermittent to pin down. Thought you guys might
have
> > some ideas. It only started recently and seems to happen the most
frequent
> > when it is really cold out and it hasn't had much time to warm up. It
> > doesn't happen every time under these circumstances, but that seems to
be
> > when it happens the most.
> >
> > Basically, it is a loud.. noise.. upon acceleration, and only when
starting
> > from a standstill and only when giving it a little more gas than usual.
> > Almost like a rattle, but deeper, coming from the rear. I thought it
might
> > be the exhaust pipe rattle against my shackle (I have 2" extended
shackles
> > and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> > doesn't make sense, though, because it would happen all the time...
> >
> > Anyhow, could this be the rear u-joint? How would I check it? Could it
be
> > something in the diff (doubtful)? I don't know, but the noise is pretty
> > loud. Loud enough to really get our attention today.
> >
> > Thanks guys.
> >
> > Eric
> >
> >
>

Re: Weird noise from rear of XJ
 

But would the diff make loud enough noises to be heard/felt in the cabin?

Eric
"Steve" <xjlfter@bogus.com> wrote in message
news:1jSOb.67875$IF6.1612418@ursa-nb00s0.nbnet.nb.ca...
> If there is water in your differential you might hear the gears chewing
> up the ice from a cold start. If you suspect this, put a pan or bucket
> under your diff and remove the cover to let the oil out. While you're in
> there, check the gears for any chips or missing teeth. If you can, lift
> one or both of the rear tires so you can rotate the gears to inspect.
> Use a quality synthetic gear oil with a good cold-temp viscosity when
> you refill.
>
> Steve
> 90 XJ
>
> Eric wrote:
> > Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises,
and
> > they are really too intermittent to pin down. Thought you guys might
have
> > some ideas. It only started recently and seems to happen the most
frequent
> > when it is really cold out and it hasn't had much time to warm up. It
> > doesn't happen every time under these circumstances, but that seems to
be
> > when it happens the most.
> >
> > Basically, it is a loud.. noise.. upon acceleration, and only when
starting
> > from a standstill and only when giving it a little more gas than usual.
> > Almost like a rattle, but deeper, coming from the rear. I thought it
might
> > be the exhaust pipe rattle against my shackle (I have 2" extended
shackles
> > and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> > doesn't make sense, though, because it would happen all the time...
> >
> > Anyhow, could this be the rear u-joint? How would I check it? Could it
be
> > something in the diff (doubtful)? I don't know, but the noise is pretty
> > loud. Loud enough to really get our attention today.
> >
> > Thanks guys.
> >
> > Eric
> >
> >
>

Re: Weird noise from rear of XJ
 

But would the diff make loud enough noises to be heard/felt in the cabin?

Eric
"Steve" <xjlfter@bogus.com> wrote in message
news:1jSOb.67875$IF6.1612418@ursa-nb00s0.nbnet.nb.ca...
> If there is water in your differential you might hear the gears chewing
> up the ice from a cold start. If you suspect this, put a pan or bucket
> under your diff and remove the cover to let the oil out. While you're in
> there, check the gears for any chips or missing teeth. If you can, lift
> one or both of the rear tires so you can rotate the gears to inspect.
> Use a quality synthetic gear oil with a good cold-temp viscosity when
> you refill.
>
> Steve
> 90 XJ
>
> Eric wrote:
> > Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises,
and
> > they are really too intermittent to pin down. Thought you guys might
have
> > some ideas. It only started recently and seems to happen the most
frequent
> > when it is really cold out and it hasn't had much time to warm up. It
> > doesn't happen every time under these circumstances, but that seems to
be
> > when it happens the most.
> >
> > Basically, it is a loud.. noise.. upon acceleration, and only when
starting
> > from a standstill and only when giving it a little more gas than usual.
> > Almost like a rattle, but deeper, coming from the rear. I thought it
might
> > be the exhaust pipe rattle against my shackle (I have 2" extended
shackles
> > and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> > doesn't make sense, though, because it would happen all the time...
> >
> > Anyhow, could this be the rear u-joint? How would I check it? Could it
be
> > something in the diff (doubtful)? I don't know, but the noise is pretty
> > loud. Loud enough to really get our attention today.
> >
> > Thanks guys.
> >
> > Eric
> >
> >
>

Re: Weird noise from rear of XJ
 

I think it may have done it in reverse before, now that you mention it.

How much was the tranny mount and was it hard to replace? Thanks!

Eric
"TSTONE3" <tstone3@aol.com> wrote in message
news:20040119014658.11576.00000280@mb-m12.aol.com...
> Does it do it under acceleration in reverse. I had the same thing going on
in
> my 2000 xj and couldnt nail it down. Changed the tranny mount and fixed
it. I
> also have a small lift on my jeep and I think this might have something to
do
> with the cheap tranny mounts breaking. I bought a polyurethane Daystar
mount
> from Mesa4x4.com and it actually rides better than it ever did. One
problem
> with the poly mounts though is they do have a little bit of a vibration
stopped
> at a stoplight at idle, if you can live with that they are great. Let me
know
> what you think, the problem with your stock tranny mount is you won't be
able
> to tell it is cracked even when you take it out, I think the rubber just
gets
> stretched and worn out. Hope this helps, please respond to my comment!
> Trevor

Re: Weird noise from rear of XJ
 

I think it may have done it in reverse before, now that you mention it.

How much was the tranny mount and was it hard to replace? Thanks!

Eric
"TSTONE3" <tstone3@aol.com> wrote in message
news:20040119014658.11576.00000280@mb-m12.aol.com...
> Does it do it under acceleration in reverse. I had the same thing going on
in
> my 2000 xj and couldnt nail it down. Changed the tranny mount and fixed
it. I
> also have a small lift on my jeep and I think this might have something to
do
> with the cheap tranny mounts breaking. I bought a polyurethane Daystar
mount
> from Mesa4x4.com and it actually rides better than it ever did. One
problem
> with the poly mounts though is they do have a little bit of a vibration
stopped
> at a stoplight at idle, if you can live with that they are great. Let me
know
> what you think, the problem with your stock tranny mount is you won't be
able
> to tell it is cracked even when you take it out, I think the rubber just
gets
> stretched and worn out. Hope this helps, please respond to my comment!
> Trevor

Re: Weird noise from rear of XJ
 

I think it may have done it in reverse before, now that you mention it.

How much was the tranny mount and was it hard to replace? Thanks!

Eric
"TSTONE3" <tstone3@aol.com> wrote in message
news:20040119014658.11576.00000280@mb-m12.aol.com...
> Does it do it under acceleration in reverse. I had the same thing going on
in
> my 2000 xj and couldnt nail it down. Changed the tranny mount and fixed
it. I
> also have a small lift on my jeep and I think this might have something to
do
> with the cheap tranny mounts breaking. I bought a polyurethane Daystar
mount
> from Mesa4x4.com and it actually rides better than it ever did. One
problem
> with the poly mounts though is they do have a little bit of a vibration
stopped
> at a stoplight at idle, if you can live with that they are great. Let me
know
> what you think, the problem with your stock tranny mount is you won't be
able
> to tell it is cracked even when you take it out, I think the rubber just
gets
> stretched and worn out. Hope this helps, please respond to my comment!
> Trevor

Re: Weird noise from rear of XJ
 

The Transmission mount is notorius for 'sagging' and if the shaft angle
changes much you will get 'noise' from the U joints. To check the
mount, simply put a floor jack under the trans and slowly lift it, if
the mount is broken the mount will totally lift off the crossbar - be
careful not to lift too far or you WILL break a good mount. You can
buy and install a new mount and most that Ive replaced require 1/4"
spacers (stack of washers under the trans mount) to bring the prop
shaft angtle back to spec.

If the the differential is a positrac, dont forget that you need to add
positrac additive to keep the clutch plates from 'grabbing'. I dont
use positrac lube but use "Lucas Oil Stabilizer" - to take up the worn
clearances of a worn diff .... the stuff has the apparent viscosity of
a 140 wt. lube oil and doesnt need the positrac. lube additive.



In article <uATOb.23829$ii6.6953@okepread05>, Eric <gymrat@cox.net>
wrote:

> But would the diff make loud enough noises to be heard/felt in the cabin?
>
> Eric
> "Steve" <xjlfter@bogus.com> wrote in message
> news:1jSOb.67875$IF6.1612418@ursa-nb00s0.nbnet.nb.ca...
> > If there is water in your differential you might hear the gears chewing
> > up the ice from a cold start. If you suspect this, put a pan or bucket
> > under your diff and remove the cover to let the oil out. While you're in
> > there, check the gears for any chips or missing teeth. If you can, lift
> > one or both of the rear tires so you can rotate the gears to inspect.
> > Use a quality synthetic gear oil with a good cold-temp viscosity when
> > you refill.
> >
> > Steve
> > 90 XJ
> >
> > Eric wrote:
> > > Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises,
> and
> > > they are really too intermittent to pin down. Thought you guys might
> have
> > > some ideas. It only started recently and seems to happen the most
> frequent
> > > when it is really cold out and it hasn't had much time to warm up. It
> > > doesn't happen every time under these circumstances, but that seems to
> be
> > > when it happens the most.
> > >
> > > Basically, it is a loud.. noise.. upon acceleration, and only when
> starting
> > > from a standstill and only when giving it a little more gas than usual.
> > > Almost like a rattle, but deeper, coming from the rear. I thought it
> might
> > > be the exhaust pipe rattle against my shackle (I have 2" extended
> shackles
> > > and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> > > doesn't make sense, though, because it would happen all the time...
> > >
> > > Anyhow, could this be the rear u-joint? How would I check it? Could it
> be
> > > something in the diff (doubtful)? I don't know, but the noise is pretty
> > > loud. Loud enough to really get our attention today.
> > >
> > > Thanks guys.
> > >
> > > Eric
> > >
> > >
> >
>
>

Re: Weird noise from rear of XJ
 

The Transmission mount is notorius for 'sagging' and if the shaft angle
changes much you will get 'noise' from the U joints. To check the
mount, simply put a floor jack under the trans and slowly lift it, if
the mount is broken the mount will totally lift off the crossbar - be
careful not to lift too far or you WILL break a good mount. You can
buy and install a new mount and most that Ive replaced require 1/4"
spacers (stack of washers under the trans mount) to bring the prop
shaft angtle back to spec.

If the the differential is a positrac, dont forget that you need to add
positrac additive to keep the clutch plates from 'grabbing'. I dont
use positrac lube but use "Lucas Oil Stabilizer" - to take up the worn
clearances of a worn diff .... the stuff has the apparent viscosity of
a 140 wt. lube oil and doesnt need the positrac. lube additive.



In article <uATOb.23829$ii6.6953@okepread05>, Eric <gymrat@cox.net>
wrote:

> But would the diff make loud enough noises to be heard/felt in the cabin?
>
> Eric
> "Steve" <xjlfter@bogus.com> wrote in message
> news:1jSOb.67875$IF6.1612418@ursa-nb00s0.nbnet.nb.ca...
> > If there is water in your differential you might hear the gears chewing
> > up the ice from a cold start. If you suspect this, put a pan or bucket
> > under your diff and remove the cover to let the oil out. While you're in
> > there, check the gears for any chips or missing teeth. If you can, lift
> > one or both of the rear tires so you can rotate the gears to inspect.
> > Use a quality synthetic gear oil with a good cold-temp viscosity when
> > you refill.
> >
> > Steve
> > 90 XJ
> >
> > Eric wrote:
> > > Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises,
> and
> > > they are really too intermittent to pin down. Thought you guys might
> have
> > > some ideas. It only started recently and seems to happen the most
> frequent
> > > when it is really cold out and it hasn't had much time to warm up. It
> > > doesn't happen every time under these circumstances, but that seems to
> be
> > > when it happens the most.
> > >
> > > Basically, it is a loud.. noise.. upon acceleration, and only when
> starting
> > > from a standstill and only when giving it a little more gas than usual.
> > > Almost like a rattle, but deeper, coming from the rear. I thought it
> might
> > > be the exhaust pipe rattle against my shackle (I have 2" extended
> shackles
> > > and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> > > doesn't make sense, though, because it would happen all the time...
> > >
> > > Anyhow, could this be the rear u-joint? How would I check it? Could it
> be
> > > something in the diff (doubtful)? I don't know, but the noise is pretty
> > > loud. Loud enough to really get our attention today.
> > >
> > > Thanks guys.
> > >
> > > Eric
> > >
> > >
> >
>
>

Re: Weird noise from rear of XJ
 

The Transmission mount is notorius for 'sagging' and if the shaft angle
changes much you will get 'noise' from the U joints. To check the
mount, simply put a floor jack under the trans and slowly lift it, if
the mount is broken the mount will totally lift off the crossbar - be
careful not to lift too far or you WILL break a good mount. You can
buy and install a new mount and most that Ive replaced require 1/4"
spacers (stack of washers under the trans mount) to bring the prop
shaft angtle back to spec.

If the the differential is a positrac, dont forget that you need to add
positrac additive to keep the clutch plates from 'grabbing'. I dont
use positrac lube but use "Lucas Oil Stabilizer" - to take up the worn
clearances of a worn diff .... the stuff has the apparent viscosity of
a 140 wt. lube oil and doesnt need the positrac. lube additive.



In article <uATOb.23829$ii6.6953@okepread05>, Eric <gymrat@cox.net>
wrote:

> But would the diff make loud enough noises to be heard/felt in the cabin?
>
> Eric
> "Steve" <xjlfter@bogus.com> wrote in message
> news:1jSOb.67875$IF6.1612418@ursa-nb00s0.nbnet.nb.ca...
> > If there is water in your differential you might hear the gears chewing
> > up the ice from a cold start. If you suspect this, put a pan or bucket
> > under your diff and remove the cover to let the oil out. While you're in
> > there, check the gears for any chips or missing teeth. If you can, lift
> > one or both of the rear tires so you can rotate the gears to inspect.
> > Use a quality synthetic gear oil with a good cold-temp viscosity when
> > you refill.
> >
> > Steve
> > 90 XJ
> >
> > Eric wrote:
> > > Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises,
> and
> > > they are really too intermittent to pin down. Thought you guys might
> have
> > > some ideas. It only started recently and seems to happen the most
> frequent
> > > when it is really cold out and it hasn't had much time to warm up. It
> > > doesn't happen every time under these circumstances, but that seems to
> be
> > > when it happens the most.
> > >
> > > Basically, it is a loud.. noise.. upon acceleration, and only when
> starting
> > > from a standstill and only when giving it a little more gas than usual.
> > > Almost like a rattle, but deeper, coming from the rear. I thought it
> might
> > > be the exhaust pipe rattle against my shackle (I have 2" extended
> shackles
> > > and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> > > doesn't make sense, though, because it would happen all the time...
> > >
> > > Anyhow, could this be the rear u-joint? How would I check it? Could it
> be
> > > something in the diff (doubtful)? I don't know, but the noise is pretty
> > > loud. Loud enough to really get our attention today.
> > >
> > > Thanks guys.
> > >
> > > Eric
> > >
> > >
> >
>
>

Re: Weird noise from rear of XJ
 

It could be something as simple as a break up of the ceramic in the cat
converter. Get under the jeep and bang on the converter with your hand. If
it makes the noise...then...
"Eric" <gymrat@cox.net> wrote in message
news:qSJOb.23812$ii6.13559@okepread05...
> Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises, and
> they are really too intermittent to pin down. Thought you guys might have
> some ideas. It only started recently and seems to happen the most
frequent
> when it is really cold out and it hasn't had much time to warm up. It
> doesn't happen every time under these circumstances, but that seems to be
> when it happens the most.
>
> Basically, it is a loud.. noise.. upon acceleration, and only when
starting
> from a standstill and only when giving it a little more gas than usual.
> Almost like a rattle, but deeper, coming from the rear. I thought it
might
> be the exhaust pipe rattle against my shackle (I have 2" extended shackles
> and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> doesn't make sense, though, because it would happen all the time...
>
> Anyhow, could this be the rear u-joint? How would I check it? Could it
be
> something in the diff (doubtful)? I don't know, but the noise is pretty
> loud. Loud enough to really get our attention today.
>
> Thanks guys.
>
> Eric
>
>
>

Re: Weird noise from rear of XJ
 

It could be something as simple as a break up of the ceramic in the cat
converter. Get under the jeep and bang on the converter with your hand. If
it makes the noise...then...
"Eric" <gymrat@cox.net> wrote in message
news:qSJOb.23812$ii6.13559@okepread05...
> Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises, and
> they are really too intermittent to pin down. Thought you guys might have
> some ideas. It only started recently and seems to happen the most
frequent
> when it is really cold out and it hasn't had much time to warm up. It
> doesn't happen every time under these circumstances, but that seems to be
> when it happens the most.
>
> Basically, it is a loud.. noise.. upon acceleration, and only when
starting
> from a standstill and only when giving it a little more gas than usual.
> Almost like a rattle, but deeper, coming from the rear. I thought it
might
> be the exhaust pipe rattle against my shackle (I have 2" extended shackles
> and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> doesn't make sense, though, because it would happen all the time...
>
> Anyhow, could this be the rear u-joint? How would I check it? Could it
be
> something in the diff (doubtful)? I don't know, but the noise is pretty
> loud. Loud enough to really get our attention today.
>
> Thanks guys.
>
> Eric
>
>
>

Re: Weird noise from rear of XJ
 

It could be something as simple as a break up of the ceramic in the cat
converter. Get under the jeep and bang on the converter with your hand. If
it makes the noise...then...
"Eric" <gymrat@cox.net> wrote in message
news:qSJOb.23812$ii6.13559@okepread05...
> Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises, and
> they are really too intermittent to pin down. Thought you guys might have
> some ideas. It only started recently and seems to happen the most
frequent
> when it is really cold out and it hasn't had much time to warm up. It
> doesn't happen every time under these circumstances, but that seems to be
> when it happens the most.
>
> Basically, it is a loud.. noise.. upon acceleration, and only when
starting
> from a standstill and only when giving it a little more gas than usual.
> Almost like a rattle, but deeper, coming from the rear. I thought it
might
> be the exhaust pipe rattle against my shackle (I have 2" extended shackles
> and one touches the exhaust pipe -- yes, yes I need to cut it..). That
> doesn't make sense, though, because it would happen all the time...
>
> Anyhow, could this be the rear u-joint? How would I check it? Could it
be
> something in the diff (doubtful)? I don't know, but the noise is pretty
> loud. Loud enough to really get our attention today.
>
> Thanks guys.
>
> Eric
>
>
>

Re: Weird noise from rear of XJ
 

Absolutely. Sound travels up the driveshafts and throughout the drivetrain.
Re the suggestion of posi lube, chatter of posi clutches is only heard going
around a corner. Posi clutches aren't moving when going straight ahead
unless on a slippery surface where one wheel is attempting to spin and the
other not. The key to making these kinds of diagnosis is paying very close
attention to the specific circumstances surrounding the noise, coast/ load/
tied entirely to speed, only at a corner, warm, cold, etc.
Steve
"Eric" <gymrat@cox.net> wrote in message
news:uATOb.23829$ii6.6953@okepread05...
> But would the diff make loud enough noises to be heard/felt in the cabin?
>
> Eric
> "Steve" <xjlfter@bogus.com> wrote in message
> news:1jSOb.67875$IF6.1612418@ursa-nb00s0.nbnet.nb.ca...
> > If there is water in your differential you might hear the gears chewing
> > up the ice from a cold start. If you suspect this, put a pan or bucket
> > under your diff and remove the cover to let the oil out. While you're in
> > there, check the gears for any chips or missing teeth. If you can, lift
> > one or both of the rear tires so you can rotate the gears to inspect.
> > Use a quality synthetic gear oil with a good cold-temp viscosity when
> > you refill.
> >
> > Steve
> > 90 XJ
> >
> > Eric wrote:
> > > Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises,
> and
> > > they are really too intermittent to pin down. Thought you guys might
> have
> > > some ideas. It only started recently and seems to happen the most
> frequent
> > > when it is really cold out and it hasn't had much time to warm up. It
> > > doesn't happen every time under these circumstances, but that seems to
> be
> > > when it happens the most.
> > >
> > > Basically, it is a loud.. noise.. upon acceleration, and only when
> starting
> > > from a standstill and only when giving it a little more gas than
usual.
> > > Almost like a rattle, but deeper, coming from the rear. I thought it
> might
> > > be the exhaust pipe rattle against my shackle (I have 2" extended
> shackles
> > > and one touches the exhaust pipe -- yes, yes I need to cut it..).
That
> > > doesn't make sense, though, because it would happen all the time...
> > >
> > > Anyhow, could this be the rear u-joint? How would I check it? Could
it
> be
> > > something in the diff (doubtful)? I don't know, but the noise is
pretty
> > > loud. Loud enough to really get our attention today.
> > >
> > > Thanks guys.
> > >
> > > Eric
> > >
> > >
> >
>
>

Re: Weird noise from rear of XJ
 

Absolutely. Sound travels up the driveshafts and throughout the drivetrain.
Re the suggestion of posi lube, chatter of posi clutches is only heard going
around a corner. Posi clutches aren't moving when going straight ahead
unless on a slippery surface where one wheel is attempting to spin and the
other not. The key to making these kinds of diagnosis is paying very close
attention to the specific circumstances surrounding the noise, coast/ load/
tied entirely to speed, only at a corner, warm, cold, etc.
Steve
"Eric" <gymrat@cox.net> wrote in message
news:uATOb.23829$ii6.6953@okepread05...
> But would the diff make loud enough noises to be heard/felt in the cabin?
>
> Eric
> "Steve" <xjlfter@bogus.com> wrote in message
> news:1jSOb.67875$IF6.1612418@ursa-nb00s0.nbnet.nb.ca...
> > If there is water in your differential you might hear the gears chewing
> > up the ice from a cold start. If you suspect this, put a pan or bucket
> > under your diff and remove the cover to let the oil out. While you're in
> > there, check the gears for any chips or missing teeth. If you can, lift
> > one or both of the rear tires so you can rotate the gears to inspect.
> > Use a quality synthetic gear oil with a good cold-temp viscosity when
> > you refill.
> >
> > Steve
> > 90 XJ
> >
> > Eric wrote:
> > > Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises,
> and
> > > they are really too intermittent to pin down. Thought you guys might
> have
> > > some ideas. It only started recently and seems to happen the most
> frequent
> > > when it is really cold out and it hasn't had much time to warm up. It
> > > doesn't happen every time under these circumstances, but that seems to
> be
> > > when it happens the most.
> > >
> > > Basically, it is a loud.. noise.. upon acceleration, and only when
> starting
> > > from a standstill and only when giving it a little more gas than
usual.
> > > Almost like a rattle, but deeper, coming from the rear. I thought it
> might
> > > be the exhaust pipe rattle against my shackle (I have 2" extended
> shackles
> > > and one touches the exhaust pipe -- yes, yes I need to cut it..).
That
> > > doesn't make sense, though, because it would happen all the time...
> > >
> > > Anyhow, could this be the rear u-joint? How would I check it? Could
it
> be
> > > something in the diff (doubtful)? I don't know, but the noise is
pretty
> > > loud. Loud enough to really get our attention today.
> > >
> > > Thanks guys.
> > >
> > > Eric
> > >
> > >
> >
>
>

Re: Weird noise from rear of XJ
 

Absolutely. Sound travels up the driveshafts and throughout the drivetrain.
Re the suggestion of posi lube, chatter of posi clutches is only heard going
around a corner. Posi clutches aren't moving when going straight ahead
unless on a slippery surface where one wheel is attempting to spin and the
other not. The key to making these kinds of diagnosis is paying very close
attention to the specific circumstances surrounding the noise, coast/ load/
tied entirely to speed, only at a corner, warm, cold, etc.
Steve
"Eric" <gymrat@cox.net> wrote in message
news:uATOb.23829$ii6.6953@okepread05...
> But would the diff make loud enough noises to be heard/felt in the cabin?
>
> Eric
> "Steve" <xjlfter@bogus.com> wrote in message
> news:1jSOb.67875$IF6.1612418@ursa-nb00s0.nbnet.nb.ca...
> > If there is water in your differential you might hear the gears chewing
> > up the ice from a cold start. If you suspect this, put a pan or bucket
> > under your diff and remove the cover to let the oil out. While you're in
> > there, check the gears for any chips or missing teeth. If you can, lift
> > one or both of the rear tires so you can rotate the gears to inspect.
> > Use a quality synthetic gear oil with a good cold-temp viscosity when
> > you refill.
> >
> > Steve
> > 90 XJ
> >
> > Eric wrote:
> > > Ok, my 00 XJ (4.0L, Auto, 8.25 rear) is giving me some strange noises,
> and
> > > they are really too intermittent to pin down. Thought you guys might
> have
> > > some ideas. It only started recently and seems to happen the most
> frequent
> > > when it is really cold out and it hasn't had much time to warm up. It
> > > doesn't happen every time under these circumstances, but that seems to
> be
> > > when it happens the most.
> > >
> > > Basically, it is a loud.. noise.. upon acceleration, and only when
> starting
> > > from a standstill and only when giving it a little more gas than
usual.
> > > Almost like a rattle, but deeper, coming from the rear. I thought it
> might
> > > be the exhaust pipe rattle against my shackle (I have 2" extended
> shackles
> > > and one touches the exhaust pipe -- yes, yes I need to cut it..).
That
> > > doesn't make sense, though, because it would happen all the time...
> > >
> > > Anyhow, could this be the rear u-joint? How would I check it? Could
it
> be
> > > something in the diff (doubtful)? I don't know, but the noise is
pretty
> > > loud. Loud enough to really get our attention today.
> > >
> > > Thanks guys.
> > >
> > > Eric
> > >
> > >
> >
>
>

Re: Weird noise from rear of XJ
 

On Mon, 19 Jan 2004 19:28:50 GMT, Rich Hampel <RhmpL33@nospam.net>
wrote:

>The Transmission mount is notorius for 'sagging' and if the shaft angle
>changes much you will get 'noise' from the U joints. To check the
>mount, simply put a floor jack under the trans and slowly lift it, if
>the mount is broken the mount will totally lift off the crossbar - be
>careful not to lift too far or you WILL break a good mount. You can
>buy and install a new mount and most that Ive replaced require 1/4"
>spacers (stack of washers under the trans mount) to bring the prop
>shaft angtle back to spec.
>
>If the the differential is a positrac, dont forget that you need to add
>positrac additive to keep the clutch plates from 'grabbing'. I dont
>use positrac lube but use "Lucas Oil Stabilizer" - to take up the worn
>clearances of a worn diff .... the stuff has the apparent viscosity of
>a 140 wt. lube oil and doesnt need the positrac. lube additive.

Do you use the Lucas product alone or as an additive? If so, what do
you use along with the Lucas Oil Stabilizer?


--
Taylor

'89 Audi 200
'03 Audi S6 Avant
'98 Jeep Cherokee Sport

Re: Weird noise from rear of XJ
 

On Mon, 19 Jan 2004 19:28:50 GMT, Rich Hampel <RhmpL33@nospam.net>
wrote:

>The Transmission mount is notorius for 'sagging' and if the shaft angle
>changes much you will get 'noise' from the U joints. To check the
>mount, simply put a floor jack under the trans and slowly lift it, if
>the mount is broken the mount will totally lift off the crossbar - be
>careful not to lift too far or you WILL break a good mount. You can
>buy and install a new mount and most that Ive replaced require 1/4"
>spacers (stack of washers under the trans mount) to bring the prop
>shaft angtle back to spec.
>
>If the the differential is a positrac, dont forget that you need to add
>positrac additive to keep the clutch plates from 'grabbing'. I dont
>use positrac lube but use "Lucas Oil Stabilizer" - to take up the worn
>clearances of a worn diff .... the stuff has the apparent viscosity of
>a 140 wt. lube oil and doesnt need the positrac. lube additive.

Do you use the Lucas product alone or as an additive? If so, what do
you use along with the Lucas Oil Stabilizer?


--
Taylor

'89 Audi 200
'03 Audi S6 Avant
'98 Jeep Cherokee Sport

Re: Weird noise from rear of XJ
 

On Mon, 19 Jan 2004 19:28:50 GMT, Rich Hampel <RhmpL33@nospam.net>
wrote:

>The Transmission mount is notorius for 'sagging' and if the shaft angle
>changes much you will get 'noise' from the U joints. To check the
>mount, simply put a floor jack under the trans and slowly lift it, if
>the mount is broken the mount will totally lift off the crossbar - be
>careful not to lift too far or you WILL break a good mount. You can
>buy and install a new mount and most that Ive replaced require 1/4"
>spacers (stack of washers under the trans mount) to bring the prop
>shaft angtle back to spec.
>
>If the the differential is a positrac, dont forget that you need to add
>positrac additive to keep the clutch plates from 'grabbing'. I dont
>use positrac lube but use "Lucas Oil Stabilizer" - to take up the worn
>clearances of a worn diff .... the stuff has the apparent viscosity of
>a 140 wt. lube oil and doesnt need the positrac. lube additive.

Do you use the Lucas product alone or as an additive? If so, what do
you use along with the Lucas Oil Stabilizer?


--
Taylor

'89 Audi 200
'03 Audi S6 Avant
'98 Jeep Cherokee Sport

Re: Weird noise from rear of XJ
 

I use a full quart of the stabilizer and then add to full with regular
gear oil.
What started this was that I had 'wierd' wear patterns develop due to
movement in one of the 'crush seals' holding the pinion in place. The
noise settled down with the stabilizer. I changed the lube a year
later and added just plain gear oil and posi-trac lube - noise came
back immediately and I then replaced with the stabilizer and oil to
quiet it down.

In article <401574b1.14053758@wilhelp.com>, Just Taylor
<taylor@wilhelp.com> wrote:

> On Mon, 19 Jan 2004 19:28:50 GMT, Rich Hampel <RhmpL33@nospam.net>
> wrote:
>
> >The Transmission mount is notorius for 'sagging' and if the shaft angle
> >changes much you will get 'noise' from the U joints. To check the
> >mount, simply put a floor jack under the trans and slowly lift it, if
> >the mount is broken the mount will totally lift off the crossbar - be
> >careful not to lift too far or you WILL break a good mount. You can
> >buy and install a new mount and most that Ive replaced require 1/4"
> >spacers (stack of washers under the trans mount) to bring the prop
> >shaft angtle back to spec.
> >
> >If the the differential is a positrac, dont forget that you need to add
> >positrac additive to keep the clutch plates from 'grabbing'. I dont
> >use positrac lube but use "Lucas Oil Stabilizer" - to take up the worn
> >clearances of a worn diff .... the stuff has the apparent viscosity of
> >a 140 wt. lube oil and doesnt need the positrac. lube additive.
>
> Do you use the Lucas product alone or as an additive? If so, what do
> you use along with the Lucas Oil Stabilizer?
>
>
> --
> Taylor
>
> '89 Audi 200
> '03 Audi S6 Avant
> '98 Jeep Cherokee Sport

Re: Weird noise from rear of XJ
 

I use a full quart of the stabilizer and then add to full with regular
gear oil.
What started this was that I had 'wierd' wear patterns develop due to
movement in one of the 'crush seals' holding the pinion in place. The
noise settled down with the stabilizer. I changed the lube a year
later and added just plain gear oil and posi-trac lube - noise came
back immediately and I then replaced with the stabilizer and oil to
quiet it down.

In article <401574b1.14053758@wilhelp.com>, Just Taylor
<taylor@wilhelp.com> wrote:

> On Mon, 19 Jan 2004 19:28:50 GMT, Rich Hampel <RhmpL33@nospam.net>
> wrote:
>
> >The Transmission mount is notorius for 'sagging' and if the shaft angle
> >changes much you will get 'noise' from the U joints. To check the
> >mount, simply put a floor jack under the trans and slowly lift it, if
> >the mount is broken the mount will totally lift off the crossbar - be
> >careful not to lift too far or you WILL break a good mount. You can
> >buy and install a new mount and most that Ive replaced require 1/4"
> >spacers (stack of washers under the trans mount) to bring the prop
> >shaft angtle back to spec.
> >
> >If the the differential is a positrac, dont forget that you need to add
> >positrac additive to keep the clutch plates from 'grabbing'. I dont
> >use positrac lube but use "Lucas Oil Stabilizer" - to take up the worn
> >clearances of a worn diff .... the stuff has the apparent viscosity of
> >a 140 wt. lube oil and doesnt need the positrac. lube additive.
>
> Do you use the Lucas product alone or as an additive? If so, what do
> you use along with the Lucas Oil Stabilizer?
>
>
> --
> Taylor
>
> '89 Audi 200
> '03 Audi S6 Avant
> '98 Jeep Cherokee Sport

Re: Weird noise from rear of XJ
 

I use a full quart of the stabilizer and then add to full with regular
gear oil.
What started this was that I had 'wierd' wear patterns develop due to
movement in one of the 'crush seals' holding the pinion in place. The
noise settled down with the stabilizer. I changed the lube a year
later and added just plain gear oil and posi-trac lube - noise came
back immediately and I then replaced with the stabilizer and oil to
quiet it down.

In article <401574b1.14053758@wilhelp.com>, Just Taylor
<taylor@wilhelp.com> wrote:

> On Mon, 19 Jan 2004 19:28:50 GMT, Rich Hampel <RhmpL33@nospam.net>
> wrote:
>
> >The Transmission mount is notorius for 'sagging' and if the shaft angle
> >changes much you will get 'noise' from the U joints. To check the
> >mount, simply put a floor jack under the trans and slowly lift it, if
> >the mount is broken the mount will totally lift off the crossbar - be
> >careful not to lift too far or you WILL break a good mount. You can
> >buy and install a new mount and most that Ive replaced require 1/4"
> >spacers (stack of washers under the trans mount) to bring the prop
> >shaft angtle back to spec.
> >
> >If the the differential is a positrac, dont forget that you need to add
> >positrac additive to keep the clutch plates from 'grabbing'. I dont
> >use positrac lube but use "Lucas Oil Stabilizer" - to take up the worn
> >clearances of a worn diff .... the stuff has the apparent viscosity of
> >a 140 wt. lube oil and doesnt need the positrac. lube additive.
>
> Do you use the Lucas product alone or as an additive? If so, what do
> you use along with the Lucas Oil Stabilizer?
>
>
> --
> Taylor
>
> '89 Audi 200
> '03 Audi S6 Avant
> '98 Jeep Cherokee Sport