Hello everyone!
I've been searching the forums for a case that resembles mine, but I haven't found anything that is quite like it. I am hoping some of you experts can guide me!

I bought a 2007 Vanden Plas with 55k miles about two months ago. The car sat for about 3 years without use. I am done fixing most of the issues it had when I bought it, and I have done all the work myself. However, there is something I just can't figure out!

The car has a constant low-frequency grinding noise that kind of sounds like droning coming from the rear wheels (more to the left). It happens when moving at any speed, and oscillates along with tire rotation. At certain speeds it also starts to shake the car up and down, as if it was a very bent rim, I have tried swapping the wheels from front to back with no luck. I changed the rotors and pads already.

I am puzzled, since it kind of sounds like a bearing, but it is rhythmic and it shakes. It also is weird that I hear it at all speeds and rotates with the wheel.

Any ideas? Differential? A specific weak u-joint?

Thank you!!

 

Did you try spinning the each rear wheel (especially the left) by hand to see if it is the rear bearing? Its sometimes hard to tell since you are also spinning the rear differential gears. You could remove the left rear axle and spin that wheel. Also check if the rear wheels have any play and if that play is the rear bearing. The bearing needs to be carefully pressed out of the rear hub.

 

If you do have a bad rear wheel bearing that needs replaced.
I would replace them both, while your up there in the air.

 

So I jacked up the back of the car today, put it in drive and let the wheels spin. The growling/low pitch metal rubbing noise comes from the differential.
I also noticed both axles R and L wobbling up and down as they turned.

Is my differential done? Could this be as simple as low fluid?

Thanks!

 

You used two jacks one on each side i hope.
Not one under the pumpkin or rear end.
Like we always did on the American cars.

 

Haha yes I used one on each side. These are my observations:

1. Only the passenger side wheel turns. Is this normal? The driver side wheel only moves slowly if at all.

2. There is play in both differential output shaft bearings. They move quite a bit when the car is accelerated.

3. I changed the fluid and it made no difference.

I see refurbished and used differentials are about $200-300 online. I am inclined to just change the whole unit.

Does this sound like it is the best way to go? If so, anybody have experience swapping a differential on a X350? Any special tools required?

 

If you can see play at the diff bearings, then your suggestion of a swap-out is the best option. It gets the car back on the road quickly.

I must say I am very surprised these bearings are worn-out at 50k miles; they normally last the life of the car as does the diff. It might be best to get a 2nd opinion before you start whacking out the cash.

 

If the rear end is really in that bad of shape.
I tend to wonder what the transmission fluid looks,& smells like.
Burn outs, & hot ******* in general.
Can tear any automatic transmission, & rear end up pretty fast.

 

Thank you all for the responses.
I am also surprised at how many bushings and suspension components are shot at 50k miles. They just look degraded. Im thinking the car might've seen some water at some point or something.

Anyone have access to a walkthrough to change the differential. I've never done one before. Do I need any special tools?

 

Hope not, a lot of flood cars out there.

 

There were known differential issues on the first years of the x350, Jag changed the diff/propshaft/axle on later models and published these as replacement parts for earlier cars. https://www.jaguarforums.com/forum/x...-noise-153427/

If you get the original diff repaired, please post back details, I'd be interested in knowing how it turns out. Mine has had a slight whine at 45mph forever.

 

I ordered a used differential from a well taken care of XJR.
At this point, I am puzzled myself. The diff does not whine like others commonly complain of. The sound is that of heavy rotating metal pieces. Almost like a wheel bearing but coupled with rear shaking, originating from the differential assembly and no wheel play.
What should I look for here? Is there a differential bearing failure that could cause shaking and growling?

Anyways, I am getting under the car and dropping it all this Sunday. I will swap the diff to see if the problem is gone. I hate the idea of doing this job just to find out the noise came from somewhere else

I will post updates but any advice is appreciated. Is this literally as simple as unbolting everything and dropping it? Is there anything I need to keep aligned or mark before removal?

 

There is a bearing supporting the driveshaft halfway down, that could be faulty. The rubber coupler at the driveshaft/axle could be worn out. Differential is mounted on bushings. Probably need chassis ears to narrow it down. Also, not sure if supercharged and N/A engines used the same gear ratio.