Hi everyone,

I'm a new member and unfortunately not a terribly technically gifted one (although I'm learning). I recently bought a 1997 Jaguar XJR X300 supercharged with only 145 000 kms. Overall I'm very happy with the car, but I noticed that when I accelerate slowly there are distinct vibrations to be felt that only stop either by accelerating more forcefully, or by releasing the throttle. It seems to be happening more continuously and mostly when the engine is warm. I was told it could be the 'donut', but at the garage they thought it was fine. Does anyone know of other causes for these very annoying (and possibly harmful?) vibrations?

Thank you
David

 

Sorry for the delayed response. Did you make any more progress on this?

Driveline vibrations as you describe could be caused by trouble (meaning wear-out) with any of these:

Driveshaft Center Bearing (#3)
Transmission mount
Engine mounts
U-joints (2 on driveshaft, 4 on rear axles)
The "donut" (Jurid coupling rubber, #5)


If any of these components were replaced in the past, vibration could happen due to incorrect installation. The driveshaft has to be aligned very carefully. If the donut was replaced, it could cause the driveshaft to be out of balance.

 

Hello Richard,

Thank you for your reply, it is very helpful!
I wasn't getting anywhere really. The donut was replaced only recently by the previous owner's garage, so that seemed unlikely.
But as you say, it could very well have been installed incorrectly which is hard for me to assess.

Since there aren't that many mechanics nearby that are familiar with this type of car, the scheme you've added could prove very useful too.
I've looked up a nearly retired mechanic that hasn't worked a lot on Jaguar before, but with this info at least he should know where to look and what to check.
Appointment on 22nd May. I'l keep you posted!

Thanks again and have a nice weekend

 

Jaguar recommends that the coupling donut not ever be removed from the driveshaft because of the balancing done at the factory. Of course if it is worn out, it must be replaced. So many years down the road, that leaves the job open to some possibly questionable work due to inexperience or unfamiliarity. Look for evidence along the drivetrain if the center bearing or transmission mount have also been moved from their original positions.

While it is possible to have the driveshaft with donut balanced again, you may do just as well to simply re-orient the donut, while checking for proper fit and correct torque on the bolts. Of course those other items of concern should be ruled out first. The center bearing is a likely suspect too.

Be sure to have the mechanic check those things, and the wheel bearings too. The rear wheel bearings should have no play in them whatsoever.

Good luck, please let us know what happens. And you are welcome!

 

Will do!
I just hope the mechanic's many years of experience on other cars will allow him to do the job properly.
Your guidelines will certainly help!

 

Also get your mechanic to check the rear Driveshaft Universal Joints. Greasing these joints is a service item that is often missed leading to failure.

Also, the Rear Hub Pivot Bearings are a known issue as they never see lubrication and can seize and disintegrate.

 

Hi Brendan,

Thank you for that additional piece of advice!

I bought the car only recently and the seller's paperwork with regard to maintenance wasn't complete.
Although a mechanic had a quick look at it before I bought it, some things only show up later, like the vibrations.
Better to put in some extra care now than be sorry later

Thanks again and I'll keep you posted through this thread!

 

Hello Richard,

I got a call from the garage earlier today. As I told you they are not familiar with Jaguar. They say they saw a rubber part of about 10cms with about 0.7cms slack to the side, situated somewhere near where the drive chain and transmission meet.
They suspect that slack is causing the vibrations.

But they cannot find any serial number, brand name or other references on it, and based on their unclear description I cannot determine what part they could be referring to. Do you maybe have an idea, or even a technical drawing like the one you sent me earlier? They say the part is not on that drawing.

Thanks,
David

 

Maybe they are referring to a part of the transmission mount. Bushing #13 MMC7553AA is well known for wearing out. It is made out of a spongy material. I don't think that alone would be responsible for so much vibration, but I could be wrong. I think the previous work done on the drivetrain has caused this vibration.





Jaguar Classic Parts UK

Diagrams complements of JCP. That site is your friend.

Looks like you and the shop have to educate yourselves about this car. There are downloads for service manuals in the stickies section here. The shop should have access to lots of service information too.

Thanks for getting back to us right on time! Good luck.

 

Thanks for this interesting piece of info.
I went to the garage after work with the drawing and took a look underneath.

When I pushed upwards against the drive chain, it went up and down at least 1cm, maybe more.
And you could see a space between to bottom bolt (n°15 on sketch) and the metal 'holder' (n°1).
The mechanic thought that not to be normal, so if he's right it could be any of the parts from n°6 to 15 that is causing it.

I took some pictures, hoping this will clarify the situation:




parts n°15, 14 and 13 from the sketch

Or should he look elsewhere for the problem?

 

And thanks for the 'stickies' tip
As a non-native speaker I wasn't familiar with the term and it took some figuring out, but I found some really interesting downloads on the forum.
Also with thanks to all the Jag lovers that put them there!

 

Hi,

At the garage they dismantled the group of parts from the drawing and turned out that bushing nr 13 was slightly bent.
Replaced it and already the car is suffering noticably less from the vibrations. So thanks a lot for pointing this area out!

Still not completely resolved though. We are wondering if the play on parts 15 to 13 isn't too big, but as it seems we cannot decrease it by further tightening bolts or anything... Is there any reference to the allowed play on these parts to be found somewhere? I haven't been able to find it so far.

If it is not the play that is the problem there must be another part or configuration that is causing vibrations.
I'm going to try and figure out together with the garage where the rest of the problem could be.
We will be changing the front shock absorbers soon, so maybe that is an opportunity to look further

Any suggestions are still welcome!

Thanks for the support already
David

 

Got stuck with a back hernia mid July, so I have a few frustrating weeks behind me.
Last week my brother was in the country and although the vibration problem isn't solved yet, together we managed to exclude some extra possible causes.

Summarizing what we ruled out since the beginning of this thread (also thanks to your suggestions everyone!):
- Tire and balancing problems, wheel bearings
- suspension problems (put in new front suspension and back bushings)
- the transmission mount
- the driveline alignment and donut
- rear Driveshaft Universal Joints and rear Hub Pivot Bearings

Everything lead us to the conclusion that the problem should be situated within the transmission itself.

To start with: it was a long search for just simply the right (contempory) identification code of the transmission unit of my car. Apparently the 1996 XJR 4.0 was the only model of that time with a GM 4L80-E transmission (not a Jaguar one, nor a Mercedes one as I was told at first by some people). It is supposed to be the same as the ones used in some heavy US chevrolet and GMC models. Unfortunately European Chevrolet dealers repeatedly told me they don't have access to US model parts.
So then an equally long search began for a simple part such as the pan gasket. Plenty and cheaply available in the US, but unfortunately with excessive transport and import costs. Nearby almost extinct and thus shamelessly overpriced by the very few dealers that had them in stock. Had to drive to Tilburg (The Netherlands) to get a decent offer (18 euro).

With the new gasket and oil filter at hand, we first drained whatever transmission oil would come out (only about 4 litres unfortunately) and it looked nasty. We then opened up the pan and noticed a lot of smudge on the bottom and on the magnet. But worst of all, it seemed that the previous owner (or garage) hadn't found a fitting gasket either when it was last opened up. They had simply reused the old gasket and smeared some kind of silicone kit all over it, so abundantly that some of it dripped out on the inside of the pan!
We now presume that some of the excess silicone may have travelled around in the transmission and damaged or blocked the pump of the 4th gear.

Without the proper equipment and knowledge to completely revize the transmission, we tried to somehow 'flush' it, hoping that would remove enough dirt. So now I'm driving with 4 ltrs of new Dextron III ATF and a new filter. Next Friday I will have driven about a 1000 kms, tap it again and add new oil, and maybe repeat that once or twice afterwards. If that doesn't help, I fear there is no other option than to have the transmission revized completely, a very costly business that I am anxiously hoping to avoid.
So, fingers crossed!

 

Hello again David, thank you for the update.

The GM 4L80E is in use in my XJ12 as well. It is a common transmission for the era in the United States. An older version (Turbo 400) was used in all the Jaguar V12 automatics until about 1994. The more modern versions of the XJR and XKR with V8 engines, will have a Mercedes transmission.

It is a good thing to get new fluid into the transmission. It holds about 12 quarts/litres, so it will take at least 4 change-outs to replace almost all of the old fluid. That may very well help it to run smoother. It is a tough transmission, but old fluid is hard on any transmission. Continue with the drain/refill cycles. Also, it is not unusual to reuse the pan gasket if it is in good condition. Additional sealant on it might seem like a good idea but might cause issues as you found out.

Lastly, the gap you pointed out at the bottom of the mount is probably due to the support springs in the mount wearing down, sagging a bit. That's expected at this age! This slightly lower position of the transmission, along with the looseness you found, could contribute to the vibrations. Now that you have ruled out many other factors, replacing those springs and the rubber seats might be necessary. Finding those parts could be a challenge. Jaguar Classic Parts might have some of them.

 

Hello Richard,

Thank you for that additional info, I appreciate it!
I have just changed ATF oil again after driving about 800kms since last refill. Still a quite dark discolouration, so you are probably right about the need for multiple refills.
This time only about 2,5 litres came out though. Even after tilting the car I could hardly get more out of it.
Anyway, I'm going to try again after the next 800kms or so.

And good to know about the gasket. I was a bit worried that it would be a problem again should the transmission need to be revized.

And I'll start looking for those springs. A contact in The Netherlands recently pointed out the same as you did, so there might also be some truth in that ;-)

By the way: my brother who lives in Spain bought me a high performance reusable K&N air filter (33-2190) as a birthday gift. Unfortunately due to a website error it didn't fit my Jag and because of the time lag between him buying it and getting it over to me, the supplier won't take it back. I looked it up and it should fit the following cars:

• JAGUAR XJ Sedan (X308) (07.1997 - 05.2003, 237 - 363 PK, gasoline)
• JAGUAR XJ Sedan (X330) (11.1994 - 07.1997, 320 PK, gasoline)
• JAGUAR XK 8 Cabrio (X100) (03.1996 - 12.2006, 284 - 396 PK, gasoline)
• JAGUAR XK 8 Coupe (X100) (03.1996 - 07.2005, 284 - 396 PK, gasoline)
• JAGUAR XK Cabrio (X150) (03.2006 - 07.2014, 298 - 416 PK, gasoline)
• JAGUAR XK Coupe (X150) (03.2006 - 07.2014, 298 - 416 PK, gasoline)
• DAIMLER Daimler XJ (X30) (07.1997 - 06.2003, 363 PK, gasoline)

Do you have any suggestions how to go about offering this on Jaguar Forum? As far as I can tell, I cannot become a 'vendor' on the forum as a private person?

Thanks and best regards!
David

 

From memory, is there not an alignment process for the propshaft? I have not had occasion to work in this area, but seem to remember some debate about how to align the various elements of the drivetrain if you have had them off, which you will have had when replacing the donut. The main point I remember is that, counterintuitively, the idea is NOT to set the drivetrain in a straight line. There is a fairly simple process to align it, but I am afraid I cannot remember it.

 

It's an interesting point that you've brought up.
I didn't replace the donut myself, but judging from it's current state, it must have been replaced no more than let's say a year ago (max 2). So I don't know if the previous owner/garage replaced it correctly or not. I seem to remember that in one of the stickies, I found a depiction of how to realign the shaft by hanging leadweights on different points.

Because the vibrations can only be felt in 4th gear and not when driving at the same speed or at the same rpm in 3rd (manual), I'm guessing that the problem is more likely to be found in the gearbox. But still, food for thought should the gearbox be in the clear, thanks!!

 

Hi everyone,
Back problems have kept me out of my car for weeks, but I'm slowly starting to dig into the problem again.
Since last time I brought the X300 to an automatic gearbox specialist, Autrac in Lint (Belgium). He hooked it up to his computer, took it for a drive and delivered a full A4 sheet of error codes. Most of them unrelated to the transmission, rather to the ignition. He advised me to wait before opening up the transmission.
He erased the lot, and I am now driving the car again under different conditions to see which ones are coming back. Strangely, the vibration problem seems to have diminished without any further alterations, although it is still present on a lighter scale.
I am carefull not to get overexcited, but it seems like an avalanche of electronic errors may have been the major cause.
One of these weeks I'll go back for a second reading. Hopefully not too much nastiness will come up.

PS: I sold the K&N Air filter that didn't fit my car to a friendly XK 8 enthousiast, so it is off the market.

 

Hi,

6 months and 3 garages after my last post. 1600 euros lighter and still the problem persists.
Last resort is replacing the entire drive chain but apparently it's not that easy to find (at a reasonable price).
And again Covid-19 is making things harder, but we keep on dreaming...

 

Hi David,

Thank you for giving us an update. Can you tell us what was done that cost 1600 euros?

Cheers,

Don