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
> >
> >
>