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My beautiful car is a 2001 Jaguar XJ8L Vanden Plas. I have recently done the following at 115k miles: complete timing service, all fluids flushed, transmission serviced, suspension bushings refresh, all wheel bearings and brakes ( pads and rotors), new alternator, new battery, new spark plugs and ignition coils, new throttle body, new continental tires fitted and road force balanced, both Cam position sensors replaced all done by certified Jaguar Techs. However as I’m attempting to give this car back to its former glory I have run into a vibrating and humming issue that is consistent at 50-68mph but only when cruising at that speed or when I coast at that speed. When I accelerate it goes away and at any other speeds it is nonexistent. The transmission shifts smooth as can be but has a slight rattle at an idle( I used a stethoscope to find out that the noise was coming from the transmission). There is no play in any of the driveshaft/prop shaft bearings or bushings and the Ujoints have no play. I’ve been tracking this issue for a while and have had the help of several shops and a Jaguar specialist and still cannot figure out why it has this vibration. Could it be an internal transmission issue? Any help is appreciated. Thank you
Welcome to the Jaguar Forums! It's great to have you with us!
I have moved your post from the forum for the X350 to the forum for the X308, which is the Jaguar factory project code for your 2001 XJ8L.
You have had a tremendous amount of work done on your car and you should be well on your way to having a wonderful daily driver. My first instinct regarding your vibration is that it may be due to a failing driveshaft center bearing and possibly the flexible couplings. The center bearing is the part shown to attach to the mounting bracket, part 7 in the diagram below:
Jaguar does not offer the center bearing as a separate part, but our member Highhorse has done some great research to find sources for the correct bearing:
The bearing is mounted above its mounting plate and is not easy to inspect without removing the driveshaft, so my recommendation would be to replace the bearing and the flexible couplings as a matter of course. I once had a problem with a new flexible coupling from ÜRO Parts that vibrated badly, and replacing it with a genuine Jaguar OEM part (made by GKN) solved the problem. Our forum sponsors Coventry West, SNG Barratt, Jagbits and Welsh Enterprises can probably get you the correct OEM flexible couplings at more affordable prices than the Jaguar dealer. Flexible couplings are also known as flex discs, Giubos, or Jurids.
Please visit the New Member Area - Intro a MUST and post a required introduction so we can learn something about you and your Jaguar and give you a proper welcome.
Bigm, I had the same symptoms, vibration at 50-70, had the driveshaft center bearing replaced, plus the two flex couplings, and the rear transmission mount. Cured the problem.
Visual inspection of the driveshaft center bearing, and/or flex couplings in-place can look fine, but age takes its toll and new items cure the problem.
Jaguar doesn't supply the center bearing, but, as per Highorse, an exact fit can be ordered.