Dear Jaguar enthousiasts,

Just bought a XJ8 350 3.5l (280.000 kms.) with a known problem. A low rumble and vibration starting at 75 kms/h and a somewhat hunting transmission at higher speed, resulting after a 15 minute drive in the announcement 'transmission failure' , P0741, P1774 and P1582. The gearbox itself is functioning alright. Oillevel is correct, oil itself clean.
The rumble is felt throughout the car and feels/sounds like something rotating unbalanced, like a household centrifuge. It is speed dependent, not revolutions.

The previous owner replaced differential, bushes and hardy-disks without solving the problem.
Could a broken (unbalanced) torque converter cause this rumble on its own, or must I be facing two different failures, e.g. a faulty driveshaft as well, maybe one causing the other. I am going to replace the torque converter anyway but before I start the operation I would like to know if anyone recognizes this problem.
Your advise will be greatly appreciated.

 

What do the codes tell you ?

When XJK near here in Newcastle-under-Lyme were operating, (stopped in Jan this year), I remember mentioning my 'hunting' syndrome and was told my car was OK, but they had had to replace a TC on another X350 where the hunting was present the whole time. Apparently the TC was completely knackered, and at your mileage, (280k km = 175k miles) it could very well cure your problem, but expensive, and I would want to be a lot more certain it would cure the problem by getting knowledgeable Jaguar or ZF autotransmission mechanic opinion.

 

Thanks for sharing your experience.
Codes tell me that the TC is not functioning well (P0741) and that this is registered (P1582), the latter resulting in the motormanagementlight coming up when the symptom has occurred three times after clearing the faultmemory.
So I will replace the TC anyway. It would be nice to know that there is a good chance that replacement will stop the rumble and vibrations, or to learn that I have to replace the driveshaft as well, which is most convenient to do so in one operation.
Yes, it is a costly operation, but inevitable. A knowledgeable Jaguarmechanic started to replace all bushes to cope with the problem. IMHO that is starting at the wrong end of the line, trying to diminish the effect rather than finding the cause. Hence my question on this forum.

 

Well, here's chapter two of probably many....(hope not!)

Changed converter with a refurbished one (by ZF), with good results, transmission works great again.
Vibration is not resolved. Changed differential with a refurbished one and no result either. The low frequent rumble appears between 80-110 kms/h and above 140 kms/h. , the latter making it almost impossible to drive at that speed, afraid of wracking the car.

Changed tires front/back: no real difference, balanced again (with road force), made all rims perfectly straight, again no result. Must continue to replace the rest of the driveline, which will cost me probably an arm and a leg.

Any suggestions that will pinpoint my search are welcome.

 

jaap. When you say it is speed dependent does that mean say at 75 kms/h there is no rumble and still no rumble if you go down a gear?

If you do not get the rumble by going down the gears at that speed I would guess it is the prop shaft at this stage.

 

You could very well be right. No rumble at speed < 75 km/h no matter what gear, rpm-independent. Also putting gear in neutral at the speed of 90 km/h (the sweet spot) does not eliminate the (harmonic) vibration. It seems a little unlikely: propshaft is quite simple and heavy, no joints, flexible couplings have been replaced by new ones.
I will give it a try and let it balance, will let you know the results!
Thanks for your advice!

 

I have the same problem in my 2005 VDP with 126,000km.
Replaced and rebalanced tires--no joy
On hoist, mechanic detected bent rear rims. Replaced--didn't fix

My thought is that it is something amiss in the driveshaft (prop shaft). But mechanic says not likely.

Back to garage next week!

 

Have you checked the transmission mount or even the engine mounts?

 

I haven't checked the transmission/engine mounts (too old to crawl under),but will suggest that to mechanic.

Both the original owner (deceased) and I live(d) in rural Ontario, so most of the kms on the car were at the 80/100 kmh speed range which is the speed at which this noise occurs, so could it be transmission gear wear at that spot?

Mechanic says both transmission and driveshaft (prop shaft) are sealed units, but I have read in Jag forums that:
1. transmission flush might solve the problem (see suggestion by RAS-XJ8, 06/23/2012 ).
2. injecting grease into driveline U joint area & half shaft (axle) cowlings corrected.

With regard to the "sealed unit" ZF transmission, RAS (above) says that there is a contradiction between what Jaguar and ZF say about transmission maintenance, (sealed for life v change oil/filter at 60k). I have the Jag service manual, but will have to hunt for the ZF, today.

 

At 280,000 kms the OP's transmission is way overdue for a transmission flush, whatever other problems there are. ZF's current advice is that the transmission fluid (and filter) should be changed at 100-150,000 kms; it's just Jag who don't seem to have caught up with that yet.

 

Just a little food for thought. Drivetrain vibrations (not dependent in RPM) exhibit themselves at some unique speeds which is fairly constant. 35~45MPH (55-70KPH) is generally found in the driveshaft or finals in the tranny itself. If the speed is 55~70MPH (85~100KPH) then you need to look at tires, wheels, hubs. The ZF's in 4th and above have the E clutch rearwards and final section engaged inside the tranny and is driveline speed. One of the most common ZF issues is worn stator bushing which seals the E clutch from fluid loss. I have experienced this only once in my ownership, at about 45MPH, and felt exactly as a broken u-joint rumble, and it was coming from the E clutch due to low fluid level from prior owner, and this happened on the drive home when I purchased in NC and had to drive home to OK.

 

I agree with the analysis. Balanced tires, straightened rims, cleaned hubs etc. to eliminate them as a cause. Flushed and refilled the tranny during the replacement of the converter. In my opinion most carmanufacturers regard their responsibility to end at about 100.000 miles, which explains their concept of 'lifetime' in relation to f.i. transmission oilchange.
But having done all that, my vibration remains, at 55 mph and at 90 mph. Next week I take the propellorshaft off and take it to an specialist for balancing.

 

Be mindful that the nuts on the bolts for the front and rear flex joints are also used for balancing, and vary in weight. Care must be taken when removing the driveshaft to return them to their exact location, including the location for the flange, joint and shaft indexing or you can create driveline imbalance. If when you removed from transmission removal, and it's index location wasn't recorded or marked or maintained, you may need to have the entire driveline balanced while in the vehicle. There is a specific procedure to accomplish this.

 

Thanks Box, that is a very useful tip. I will mark the exact position before taking it apart.

 

Just be mindful the reason I'm letting you know this, is that this issue may be the product of previous transmission removal, and not assuring the driveline alignment was maintained. The driveline should go through a rebalance procedure, which requires dealer engagement, as they have the proper special tools.

 

Finally tackled the problem. Found a used propshaft on Ebay, (Auto Reserve Ltd, great service!) for a very reasonable price (€ 100 including sending it from UK to Holland), mounted the complete set just to test if it would change the behaviour, and voila: all rumble and vibrations gone. This comes to me as a pleasant surprise, considering the previous precautions.

 

My car is an XJ40 from 1992 and I have a similar vibration. I've changed the prop shaft, but still the same. Do Jaguar dealers have the ability to check the balance status of the prop shaft etc?

 

could be anything but on my car a few things caused vibrations like this.. you can try changing the center support bearing. That's one Main issue also any of the cush drives if one is bad itll just rattle so loud when trying to take off even a lil bit fast.. or it could be a faulty torque converter.. the tranny mounts usually don't cause vibrations even if they are bad.. but it could still be.. just check if anything looks worn out near the tranny and driveshaft.. usually the torque converter will start to make a vibration while shifting up into gears or at higher gear speeds.. if it is the torque converter. The xj8 is a sensitive car.. even something super small and cheap can cause something that seems bigger than it really is..