Was on the highway tonight, heard a small thump from underneath the car like I had ran over something small and when I tried to press the gas - it was doing absolutely nothing.

Pulled over to the shoulder, put it in park and heard what I assume was the parking pin. (Same noise you get if you toss a car in park while it's still moving)

I shut the car off, started it back up and the noise was gone. I put it in drive, still nothing. I've checked under the car the driveshaft is still intact. I wiggled one end and the other, no play between the two shafts.

Am I looking at a transmission replacement?

It's a 98 XJR






UPDATE - UPDATE -

Got underneath the car, put it in reverse (in the event anything happens, it will hit my concrete wall/fence) and the driveshaft spins up to the differential - but stops there and the diff does not spin. Any idea how hard of a swap this is? And what differentials I can use? Any 98-03 XJ8's? Or XJR only?

 

You may need a transmission ie something stripped out inside but I would guess that you have a problem with something stripped out or broken between the driveshaft and the rear wheels. I would suggest, when you have the car somewhere safe, to support the rear of the car and with the transmission still in park try and rotate both rear wheels in the same direction at the same time. you should then be able to figure out where things stop turning (remember the transmission is in park). Both rear wheels should not turn if everything was correct. Start looking for where one thing is turning and the next part is not. Hope this helps.

 

x42bnx it would be most helpful if you put your vehicle information in your signature. Knowing the year and model would give us more info to work with.
The XJ8 has the BMW transmission and the the known weak link is the A drum. Assuming you have an XJ8 the sounds of the occurrence are typical A drum failure.
If it is XJR then it has the Mercedes transmission and that would be a different diagnosis.
Let us know what you have and we can go from there.

 

It's infact a 1998 XJR

 

To eliminate any of the other drive line components have someone engage the transmission and observe if the drive shaft moves. When I lost the A drum I couldn't go forward but reverse would give movement.

 

Sorry to hear -- that's a new one. Was it making any sounds prior to failure?

I have never heard of one going like this? Maybe you can fix it ?

It's more involved then typical -- we have another current thread where someone is looking for a replacement -- do a search. Thread has some information.

 

So with the car stationary, and in gear, the shaft entering the differential is turning, but the car isn't moving?

I'd say that's a pretty definitive differential failure, unless one of the shaft from diff to the rear wheels has failed.

 

stupid question but the test was done with both rear wheels off the ground?

unless you got a clean break somewhere, there should be some nasty
ginding noises going on.

any differential from a X308 will fit, SC does not matter.

 

Up to the differential itself, the driveshaft is spinning. I don't know any other parts that it could be. Before I order up a differential is there anything else, seems pretty conclusive to me. Is there a chance the flange that goes into the differential is stripped?

 

Sorry to double post on this thread,

But based on visual inspection - it spins up to this point (circled)

 

well that's all wrong because it is a picture of a diff from a S-Type or post 2003 XJ.

but, it does show the rubberised Jurid coupling at the far right which might
be a problem, although it would have to be in really bad shape to not spin
the wheels at all when both rear wheels are off the ground

yes, the flange can strip although not really heard of in this model

if it is stripped you are still looking at replacing the diff as the pinion
is not obtainable.

 

Okay, I was only attempting to verify that the correct part needs replacement. I didn't want to buy a differential and have it be some smaller part that could possibly connect to the driveshaft.

Thanks for the help I'll order the differential up

 

The Yolk on the bottom of the differential indeed does spin. What else would break? It actually makes no noise except for a spinning (thunk thunk thunk) that isn't very audible.

Before this happened, I had a slight "tink" noise that I would get coming to a stop and taking off after using reverse. It's been there for months, I originally thought it was the center support bearing on the driveshaft. When I inspected it, I found no play on that part and never got around to any further inspection.

 

x42bnx,

I'm sorry to hear about your very strange problem. If the input flange on your diff is turning, but neither output (axle) flange turns, there must be an internal failure in the differential. Does your diff show any signs of fluid leakage? These GKN diffs are generally very robust, and except for worn pinion and output shaft bearings, I don't recall hearing of many, if any, failures.

I believe the diff in your 1998 XJR will be a GKN model 14HU with its pinion (driveshaft input) on the centerline, like this:

Jaguar XJ8 Vanden Plas Drivetrain Differential 1998 1999 2000 2001 2002 2003 | eBay


According to jaguarclassicparts.com, the diffs were the same in the XJR and XJ8, with only the 3.06:1 ratio available for the XJR. The Jaguar part number changed at VIN 846052, which was during the 1998 model year. The ratio remained the same, so I don't know what other changes may have been made:

Differential Assembly - Parts For XJ Series from (V)812317 to (V)F59525 (X308 - Canada/Mexico/USA) | Jaguar Heritage Parts UK


The photos at the link below show the diff in our '93 XJ40, which is a little different from yours with an offset pinion, but it was also made by GKN and is internally similar. Some of your suspension components will be different, but the photos will at least give you and idea of what is involved in swapping in a new diff and what is inside the case that may have failed:

Diff Removal & Installation
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page

Diff Rebuild / Internals
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page

Diff Output Shaft Bearings (the X308 setup is a bit different)
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page


Cheers,

Don

 

Thanks for the reply Don, I ordered a used XJ8 unit with the hopes it will have less stress on it. I do admit to being a little hard on my car, but nothing that it shouldn't be able to handle.

My only concern was the driveshaft, but since it turns up to the differential I assume it's probably OK.

When my diff. failed in my LS1 Camaro, I had a loud whining noise and then a thumping noise. That may have something to do with be a worm-style torsen differential where the gear contact is straight to the pinion from the input shaft.

I have a feeling that it stripped out completely inside though. I was getting a ton of wheel hop at the track.

 

Here is a video that I've taken of it to alleviate any of the questions..

 

Bump

 

Can you rotate the rear wheels?