Getting a judder under accel. and a pulsing shudder at 50 mph. Not related to engine speed, just road speed. Not major but noticeable. Today I jacked up the rear and ran up to speed and got the symptoms. Next I blocked each side so that only one wheel would spin. At high speed I did get some vibration but it seemed like wheel/tire imbalance. No pulsing at 50 mph. So the problem only occurred when neither wheel was stopped.

The half shafts look good both having a small amount of in and out play (~.2 in). The diff is full. No detectable play in either wheel bearing.

Thanks for any help

 

To eliminate tires, remove them and use at least 3 lug nuts against the rotor and spin it up again. You may have to use acorn style nuts.

 

Hi raschwar,

+1 on Box's suggestion.

Tire imbalance or a bent wheel can definitely create speed-dependent vibrations.

Another possibility is the rear driveshaft flexible coupling or maybe the driveshaft center bearing.

Please keep us informed.

Cheers,

Don

 

Thanks for the suggestions. I did look at the rear coupling and it seemed in excellent shape. The tires are all new but that doesn't mean something is not still out of balance. The vibration was there before I got the tires and didn't change but I guess it could be a wheel. Running with wheels off will tell.

I'm still curious as to why it didn't vibrate when I kept either wheel from turning.

I'll keep you posted.

 

I removed both wheels and the vibration is still there, in fact worse with tires and wheels off. Afraid it's the propshaft or some component. I held a wooden hammer handle against the rear flange and could feel the pulsing.

What do I do next? Is it true that the entire propshaft and couplings must be replaced as a unit?

 

The Coupler is listed as an s type part. You can use this as they are the same. Replacement center bearings are also now available on Ebay. Check the Stype forum as one member just replaced one

Cheers
34by151

 

This seems to be coming up a lot lately. There's a sticky that mentions that the black donut couplers get worn after 8 to 10 years.
The symptoms I'm having are a fine, fast vibration that starts around 45 MPH and fades back out somewhere around 70 MPH; it's somewhat more pronounced when she's pulling. It definitely seems too fast to be a tire. Hopefully it is the donut as they seem reasonably inexpensive and from what I can see, don't seem like they'd be difficult to replace. The Service manual recommends new bolts anytime the assembly is taken apart which is probably a good idea.

 

34by151 - Thanks for the info

Is there a visual check for a bad coupler? I did look at the rear one and it looked to be in very good shape, like new in fact. But I haven't looked at the front.

 

Other than visual and giving it a good shake no

The only real ways to know is to run it up in a balancer or to replace them

Cheers
34by151

 

Dear Jag-Lovers,

owning a 2005 Jaguar XJ 4,2 NA with only 50k miles on the clock for half a year now, I am currently hunting a speed-related soul-destroying vibration. Symptoms are quite similar as user @pianohero described above: Slight vibration/roughness at initial acceleration/take-off that fades out up to 30 mph. Then it fades slightly back in. It has a peak at 50 mph and fades out at around 70 mph. There is no vibration above 70 mph. No drone when vibrating. Vibration is felt in the steering wheel, floor pan, seats. It‘s only speed related, no rpm or throttle relation. Vibration is harder the lower outside temperature is. After driving for a while the vibration gets a little bit better.

I already replaced front lower control arms that fixed steering vibration when braking. I also replaced all brake discs and brake pads. I replaced all of my tires and get them balanced.

With a special vibration app I figured out, that the vibration seems to be at propshaft speed. I suspected worn mounts which usually lead to improper propshaft angle. Hence, I played around with shims to change the rear differential angle which should affect propshaft angle. Unexpectedly, it had hardly impact on the vibration.

Now I am wondering what might be the cause of my (propshaft related) vibration. I might replace the transmission mount next.

Do you folks have any suggestions on how to fix my vibration?

@pianohero Did you manage to fix your vibration in the meanwhile?

Thank you so much!

 

busted center support or flex disc

 

Thank you. Rear flex disc looks fine, no cracks and by no means busted. The XJ only has 50k miles on the clock. Can flex disk and center support already fail at such low milage?

I‘m very curious if and how @pianohero fixed his vibration.

 

@pianohero Did you solve your vibration problems by replacing the flex discs (black donut couplers)? Thanks

 

I am having the exact same issue on my 2004 XJR with 85k miles. Vibration in the driveline from low speeds up until highway speeds and then at 70mph and above it goes away. There is also a low noise associated with it which sounds speed dependent. I've been going around replacing various parts (which eventually need replacing) like the front wheel bearings, transmission mount, differential fluid, transmission service and still the noise and vibration remains. I know its not related to the wheels and tires since the issue is the same when using the summer wheels/tires and the winter wheels/tires. At this point I've narrowed it down to being either the prop-shaft center bearing or the pinion bearing in the differential going bad. While I was having my tires replaced today I asked to have the wheels checked for bends but they found no issues. The did suggest that the 2-piece lug nuts can swell overtime from water and corrosion, though I'm a bit skeptical it could create this kind of vibration especially with the lugs being so close to the center of the wheel.

 

Watching this thread as well, before I put my 2004 Super V8 away for the winter I had a similar vibration as described above, ok my car has done 193000 miles but this is something I will need to look into when it comes back out in March or whenever the weather is better.

 

Hi guys, any news from my vibration-stricken fellows?

I continued testing last weekend and made a very strange discovery: I replaced the right wheel on the rear axle with the emergency wheel from the trunk. To my astonishment, the vibration and roar had completely disappeared. After that I reinstalled the normal right rear wheel again and installed the emergency wheel on the left side of the rear axle. Again, the vibrations are completely gone. What can that mean now? My first thought was that the narrow emergency wheel (size 135/80 R18) has a different rolling circumference than the normal wheels (255/40 R20). This would mean that the rear wheels turn at different speeds and the differential is loaded differently. This could possibly reduce vibrations of the pinion gear, which would otherwise be distributed throughout the car via the propshaft (the pinion gear rotates at exactly the same speed as the propshaft and according to the NVH-app that would be exactly the vibration frequency). However, the difference in the rolling circumference of the emergency wheel is minimal (minus 2%). I don't know if my theory is correct and it is also difficult or impossible to check without disassembling the differential.

Another theory would be defective wheel bearings on the rear axle, which only vibrate with the large Sepangs due to greater lateral loads, but not with the emergency wheel. However, in this case, both rear left and right wheel bearings would have to be defective at the same time. That is probably rather unlikely.

What do you say about this strange behavior of the vibrations with the emergency wheel? Ideas are very welcome.

Anyone replaced flex couplings or overhauled the differential so far and got any experience?

I want to finally get rid of those nerve-racking vibrations and enjoy my cat.

Thanks to all of you!

 

at this point I'm quite certain that it's the pinion bearing in the differential. A few things lead me to this conclusion. One is that when the weather is very cold, the noise is not heard until driving for a short time when the mechanical components warm up. Also I read that the differentials were made by Ford and that the earlier model years of the X350 had differentials that were more prone to having issues but the issue was resolved for the latter model years. I have an indie shop near me that rebuilds differentials so that's my next step. Hopefully they are able to identify an issue and rebuild the diff.

 

@brianlb13 Thanks for your reply. Please keep my updated on your progress and results! :-)

My next step is to test another set of 17“ factory wheels that I just bought yesterday. With these wheels I want to check my Sepangs to exclude them beeing the vibrations culprit. I also want to check what happens when I mount one (or two) of these wheels on the rear. See if I got the same effect as with the spare.

 

I had a vibration that felt and sounded like a rear wheel bearing. It developed into quite a howl, more pronounced going left than right, and different speeds. Finally changed out the wheel bearing, which did have a bit of play and roughness when removed. Seemed to help for a very short while. However came back just as bad after a few miles.
Went looking for other reasons and found a tiny bit of play in the rear outer track rod bushing. Changed that out and so far so good! Apparently the wheel would start to flutter at different speeds, angles and power applications.

 

Well, I got an update on my issue. Meanwhile I bought a set of original Jaguar 17“ wheels with winter tyres. First I put one of them on the rear right side: No change in vibration. Then I put one on the left rear. No change again. So my theory of different rolling circumference and differential seems to end in smoke. But I continued testing. Put both 17“ wheels on the rear: Absolutely no change in vibration. I was confused because up until then I was completely convinced the vibration is coming from the rear. I continued again. Left the rear 17“ on the car and put another 2 on the front so the car was completely on 17“ wheels now. Big change! The vibration was almost gone. What a stunner! Only miniscule vibration felt at exactly the previous peak at 90 kmh/55 mph. Otherwise smooth as glas except the rough winter tread.



So obviously my vibration comes from the front not the rear. Then I put back on the former FRONT 20“ on the rear while leaving the 17“ on the front. No change, good feeling as with the complete set of 17“ retained exactly the same. So got proof that the former vibration is not from front wheels neither from differential, propshaft etc. I continued and added the former BACK 20“ on the front i.e. I got the whole set of 20“ back ob the car with front and rear switched. Result: Not as good as with 17“ but definitely better than before.



My personal conclusion: As the 20“ have been road force balanced and checked on out-of-round intensely and the vibration can also be felt with the 17“ wheels (in a weakened form) the vibration must originally not be caused by the wheels. My guess is that there must be something wrong on the front axle that causes a vibration that is felt more clearly with the big and demanding 20“ wheels than with the voluminous 17“ tyres.



So far I only replaced the front lower control arm before that resolved a high speed brake shudder. All the other stuff is original with 50k miles/80k km.



Checked the front yesterday: Left front wheel jacked up no vertikal or horizontal play, right side jacked up no vertikal play but when im trying to test horizontal play i can feel a considerable amount of play in combination with metallic clunk and movement of the steering wheel. Is that normal behaviour? Its a left wheel hand car. When right front wheel jacked up I have the same considerable amount and clunk in the steering wheel. With both wheels on the ground or only left side jacked up there is no play or move at all.



As the old front lower control arms looked like new but made a huge improvement after I replaced them I‘m about to renew the whole front axle: Rear lower control arms, upper control arms, stabilizer bar links and bushings, inner and outer tie rods, brake discs and pads as well as wheel bearings. I want to finally get rid of this fu**ing vibrations/shudder!



Any thoughts, guys?



Thank you so much.