Just turned 100K. Yeah, the Jag service tech said to try and get an alignment and check the bushings(if I wanted too). He still didn't think it was bad.

 

Easy for HIM to say, right?

This sort of thing can be like the proverbial Chinese water torture for some of us. Well, me, at least. Most of my driving is on the highway. It's hard to ignore a vibration that's 'there' mile after mile after mile.

Cheers
DD

 

Is it a vibration or a humm / whine?

I have a whine coming from my rear ( the cars rear that is....lol )....that seems to be down to the diff.

I've tried a fluid change and its quietened down a little, may try it again in the next few weeks, but it may be a replacement diff.

Jaguar are quoting around £3k I believe parts / labour and Mackies transmissions say they will remove and refurbish for around £1k so no brainer there!

Having said that, I have an appomtment on Monday at Prestige Jaguar and an engineer is coming out to look at it........I'm trying to claim on an aftermarket warranty ( not holding my breath on that one )

 

Vibration, no whine. In fact that Jag tech said "if it was the differential, you'd hear a whine."

I notice the vibration is more prevalent when on the throttle and lessens when I let off. So I cannot see how this could be suspension related, but I'm new to Jags so I may be wrong.

 

If it's dependend on throttle, it might be the wheel adjustment or the propshaft.
I recorded the noise as .wav and did a frequency analysis. The frequency was 3 times the rpms of the wheels: this meant propshaft, which was to change in my case.

 

I suspect U-joints should be on the top of your checklist as a faulty UJ can feel worse under load.

I'm not familiar with the details of your model but, for example, my old XJR has six u-joints UJs. Two on each drive axle shaft and two on the driveshaft/propellor shaft. The driveshaft also has a center support bearing and a rubber coupling at the diff.

Some Jags have no driveshaft UJs. Just rubber couplings and the center support bearing.

Anyhow....

Checking the UJs means actually feeling them operate and this means disconnecting and/or removing whatever shaft they're on so you can manipulate them with your hand. For example, my front driveshaft UJ was smooth as butter when operated in one direction but very stiff and uneven in the other. This obviously cannot be determined by visual inspection.

(Since the drive axles and wheels turn at the same speed this is where the vibration analysis is helpful... as you'll know if the vibration is at wheel speed or driveshaft speed and thus know which shafts to remove)

At this point my ignorance as to how your model is built might begin to do more harm than good so let's wait for others to chime in.

Cheers
DD

 

Here's a thought, just spitballing here.

Maybe this is a front wheel bearing issue? The reason I say this is the Jag tech did notice(as I did)a slight steering wheel vibration. To me, it had nothing to do with what I was feeling at 50 since it was more pronounced during acceleration which made me believe it was a drivetrain issue. What if by accelerating, it took enough weight off the front wheels to amplify the vibration/bad bearing?

Just remembered another instance that may be a clue. Before I had the new tires put on we had an ice storm. The car was covered in ice except the windows so I could get to work. During that drive, there was hardly any vibrations. I thought it was odd, but I forgot all about it until this morning.

It seems weight had a factor in these vibrations. This would also point to the front wheel bearings, IMO.

Cliff notes:

-Vibration at 50+
-More pronounced during acceleration.
-Firestone tech road forced wheels.
-Firestone tech ran car at 50 on lift, felt the rear control arms noticed nothing out of the ordinary(no vibrations). He felt a slight vibration in differential. He said the prop shaft was fine and tight.
-Jag tech didn't notice anything too out of spec. Seemed fine to him.
-Weight seems to play a part in vibrations.

From the Carfax I got when I bought this car:

-Original owner had tires balanced 6 times during ownership.
-Original owner had differential serviced & fluid changed at 66K.
-Original owner had miscellaneous tires changed over the course of ownership(one here, two there).
-Original owner had 4 alignments within 20K miles. (44K-66K)

Looks like the original owner was trying to chase down this vibration too.

I'm wondering if maybe everyone is looking in the wrong place? I'm going to email that dealership and see if any vibration complaints were noted.

I WILL find this and fix it!!

 

IMHO this is plausible....but less likely than some of the other possibilities. In my experience a loose wheel bearing will typically give a shimmy or wobble, not a vibration....if you get the distinction.

OTOH I've also learned that not every car responds in what I would consider a 'typical' fashion.

When you are going after a problem like this you often have to simply eliminate the possibilities as you come across them. So, fix the wheel bearings and hope for the best.





Which, frankly, is almost meaningless. From this we know the prop shaft isn't loose...but that doesn't prove that it is 'fine'.



Either he genuinely believes that or he doesn't want to get involved chasing down what is likely to be an elusive fault.

If the latter, well, I can attest that there is legitimate reasoning behind it....but he should say so outright.


Cheers
DD

 

I know the front bearings seem far-fetched, but I'm just trying to have a few ideas and where to start.

The Firestone Tech meant tight and far as the rubber coupling bolts between the shafts. Yes, it could still be a bad coupling.

I'm just waiting for the original dealership to respond to my inquiry about any vibration issues my my car. I will go from there.

Thanks!

 

A rapid vibration is the drive shaft. If the joints are not loose, then the shaft may be out of balance. Or, if you hit something on the road or a knumb nut jacked the car and hit the shaft...it could be bent. For a slight vibration like you describe, it may not be possible to "see" the problem just by looking at the shaft while it's spinning.

It can also be out of balance if it was ever disconnected and the couplers were not returned to the original orientation.

Check the couplers for wear/orientation, and after that google for drive shaft balancing in your area. For a reasonable price a decent shop can straighten and balance your drive shaft.

Bearings, wheels, and tires vibrate at less than 1/3 the speed of a drive shaft vibration. Once you feel the difference once, you can never confuse the frequency of the 2 types.

 

I agree, broadly




I hate to beat this into the ground, and I'm not trying to pick on you, but I must emphasize being 'not loose' doesn't mean that a UJ is good.

A loose UJ is obviously on the verge of destruction. It didn't go from 'good' to 'loose' overnight. It was preceded, I can virtually promise, by a period of being too tight....seizing up. This is easily felt when you articulate the UJ by hand ....and the stiffness/seizing can certainly cause a vibration.



Cheers
DD

 

Precisely...but you still need to look it over before diving in. It's also why I personally would take the car to an axle shop once I failed to see any obvious issues.

 

Did you try rotating the tires to see if there is any change to the vibration?

 

Not sure if either tire place switched them around or not when the balanced them.


At this point I am almost certain it is the prop shaft. I am going to get it in the air this weekend and check the bolts first. My problem is finding someone that balances them around here. I may just buy one off ebay and install it and see what happens.


How hard are these to remove?

 

I think you need to drop the exhaust out of the way to get it out. Kind of tricky job on jack stands, a lot easier with a lift.

 

I'll have someone do it. I do have a warranty from the dealer with C.A.R.S. They do cover the driveshaft w/ a $100 deductible.

 

OK, so I have been hunting this gremlin for well over a year now. I have had countless trips to the dealership, indy and tire specialists, and I still have a vibration.

The one thing that no-one has looked at in detail are the flex joints, U-joints and center bearing. Even though I asked the dealer to go over everything with a fine toothed comb and spend as many hours as they liked. I'm sure they didn't.

Anyways, my $$ are now on worn flex joints. I can remember reading a post from someone with the same symptoms, flex joints looked fine while on the prop shaft, but when replaced the vibrations were gone.

I don't have any time right now to have them replaced, but I would recommend to have these looked at before replacing a perfectly good prop shaft. I will start replacing every piece of this assembly until I have found the problem.

 

Are you talking about the flex disc or "jurid coupling"?

EDIT: Spoke with a Jaguar Parts guy and they do not sell the flex disc separately. You have to buy the whole prop shaft @ $1400.

The coupling is now part of the shaft starting from 2004+. This is why I couldn't find just the coupling online anywhere.

 

If the coupling is marked with a manufacturer's name and/or part number, it might be possible to source it either directly from the manufacturer or through a third party industrial supplier. For example, here's a webpage for flexible couplings from GKN, one of the largest manufacturers of constant velocity shafts (and the manufacturer of both the differential and Jurid flexible coupling on our '93 XJ40):

Home - GKN Land Systems

I haven't inspected the rear end on our X350 yet - thankfully I haven't needed to, but I hope all the folks with vibration issues can sort them without having to spend big money on a new driveshaft assembly.

Cheers,

Don

 

Hi Don!

Thanks. The Jaguar dealer could not find a part number for just the coupling, only the whole assembly. He says the 2004+ models have them affixed to the shaft. This explains why in my research online, I could only find the coupling up to 2003.

I just came back from the Firestone Auto center and talked with the manager about the vibration. He agreed that the driveshaft is the culprit and will be contacting my warranty company for replacement on Monday.

Looks like $1400 for the shaft and whatever in labor. I feel 99% sure this is the issue. Whether it is the flex coupling or the center bearing, the shaft is off. If it turns out to not be the shaft, I'm out $100. At least this will narrow it down considerably.