Hi all. Firstly, I hope the Moderators or anyone else doesn't mind me starting this new thread regarding an age old problem, that is low frequency vibration/rumbling between 50 & 70 mph. Whilst I would normally ask questions within an existing thread (and have done) the threads I've read have lots of useful information but, in reading them I realised the problem can be due to so many factors, and in lots of cases refer to items I have already renewed or ruled out. So before having pages and pages of posts that are already 'well oiled', I have some specific questions I'd like to ask that only refer to the driveshaft and its fittings. BTW, the rumbling on my car has been there right from day 1 when I got it, and seems to be the whole car rather than the front or rear, there is no rumble or anything felt through the steering wheel. For info only.. to date I've changed the following:

Gearbox (for other reasons than the rumbling), Gearbox rear mounting, gearbox end and diff end Jurid couplings (but not both at the same time), prop-shaft (including new centre bearing, U/J and balanced), full set of rear sub-frame and mounting bushes, new rotors pads and calipers all round, 4 x rear drive axle U/J's, inner & outer rear wheel bearings, and wheel balancing, I've even tried different wheels and tyres... so far nothing has worked.

I have 2 new couplings to fit, as said, they were changed at different times during all the above, hence I have some questions. If any of my questions appear naive, or even stupid, please forgive me... I just need to finally get this right.

Q1) I assume the bolt goes through the coupling in the direction of the arrow? If so, this is where I got one wrong as I had limited room and vision when fitting! I guess the marks are there for a reason so, Could this be the problem?

Q2) The X308 'bible' says.. "To preserve 'drive-line' refinement, individual parts, other than fixings, MUST NOT be renewed" ... "Under no circumstances may the flexible (Jurid) coupling be removed from the driveshaft..."
So how can we fit new couplings if we're not supposed to remove the old ones? Even if we renewed the couplings and driveshaft together, they would still be alien to each other initially? One suggestion, that may appear to some as obvious, was to have the driveshaft balanced with the new couplings fitted, is this the way it should be, or is there something else I've missed? Could this be the problem?

Q3) The centre bearing is fixed to a cross plate, in between this cross plate and the centre bearing there's 2 flat spacers, 1 thick and 1 thin. You can purchase the thicker spacer individually but, the thin one comes from Jaguar in packs of 5? why 5? Should a combination of these spacers be used to achieve a specific height for the centre bearing or not? Could that be the problem?

Q4) If a combination of 1 thick and up to 5 thin should be used to achieve a specific centre bearing height, what should that height be?

Q5) If the centre bearing should be at a fixed height, why have 2 in the first place, just have 1 that is the exact/correct thickness?

The only changes I have made that may have affected the 50 to 60 change is moving the cross plate slightly, though again the bible says to make sure the driveshaft is bang central.

The one thing that sticks out to me is the statement, basically "leaver it alone", and the only way I can see around replacing parts that fail is to use the suggestion of balancing the shaft WITH the couplings on, how else could even Jaguar do it during manufacture?

If anyone can throw some light as to what else could be wrong here I would sincerely welcome your comments and advice.
Paul

 

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No naive or stupid question here, and I feel for you that you still have the 50-70 vibration after all that you have done.

Usually, replacing the center driveshaft bearing/Jurid couplings/rear transmission support bracket cures this. And you have gone further with rear sub-frame mountings, U/Js, wheel bearings, wheel balancing, calipers, etc. etc.

I'd be pulling out hair I don't have. The only suggestion I can offer is the way my 50/70 vibration was diagnosed was the alignment shop I went to put my car on their overhead lift, jacked up the car on the axles, removed the wheels, and "drove it" as though on the road. Mechanics underneath observed the movements/vibrations/anomalies at various speeds, and, quickly, visually, isolated the source to the drive shaft. I can only think that after all that you have done that this must/should be the only way to try and discover the area at fault.?



.

 

Yes, this may be a problem but not necessarily. If wrongly installed, the thinner sections of the coupling would be under compression (at rotation during forward car movement) and, being thin, they could buckle to one side and cause wobble. Otherwise, the coupling would not last very long in this orientation. The correct way is with the arrows pointing towards the "fingers" of the flanges, i.e. the thicker sections of the coupling should be under compression:



This warning in the manual is not clear to me. The couplings are shown in the parts catalogue as separately supplied so I don't think replacing them would cause any problem.

I guess it is just how they are packed by some suppliers. For example, SNG Barratt sell them individually. A combination of thick and thin (or thin only) in the required numbers should be used to set the correct height of the centre bearing. However, the manual says nothing about this. On my previous Daimler Double Six and a number of BMW-s, the requirement was to position the centre bearing slightly offset to one side. In the case of X308, I would experiment with setting the centre bearing at different heights (push it slightly higher than the ideally central) using the spacers.

 

One more thing: make sure all propshaft coupling bolts, nuts and washers are the same, i.e. exactly the same weight.

 

Thanks to you both for your replies, this helped enormously.

Today I took off the driveshaft, and sure enough, 3 problems became apparent. Firstly (on the diff end) I had the arrow pointing away from the flange. Secondly, the bolts were in the wrong way too (quite how I did that I don't know ). The third problem was at the gearbox end where I had different bolts, nuts and washers. Indeed, the information from M.Stojanvic isn't included in the book, again, why I don't know . Maybe Jaguar never thought about changing 'just' the Jurid couplings, and that their mention of never removing them (unless you replace everything including the shaft) was enough, who knows?

Reading only the book, not knowing the information from M.Stojanvic, how even a different washer/bolt/nut can affect balancing because of weight differences, how the whole unit including the couplings should be balanced as a whole, correct orientation of the coupling, direction of the bolts etc. etc. could be why so many people have this problem? Maybe it's a combination of these 'unmentioned in the book' things that has given the X308 the reputation for rumbling it has? It would be a good idea to ask a Moderator if this could be made a 'sticky' at the start of the Forum, or someone write a definitive guide as to how to fix it? Anyway, I haven't fixed it yet, so we will wait and see!

Here's the driveshaft ready to go for balance.

As you can see, the driveshaft is in good nick as it was only balanced and had new bearing and UJ about 3 months ago.


The Gearbox end, with new Jurid coupling on and the Diff end with the new Jurid coupling on


The Centre Bearing and UJ were still in good condition too.

From the pictures of the Jurid couplings, I hope I've got them on the right way this time? Please let me know if not. I even took the plunge and got a full set of new bolts, nuts, and washers from Jaguar but, there lay another load of issues from Jaguar!
1) £1.87 each plus 20% tax for a 12mm bolt!
2) The washers come in packs of 10, even though to completely renew you need 24?
3) The Jaguar part number for the 12 locknuts (NV112051J on the JaguarClassicParts website) is wrong, that part number is for 8mm locknuts?


Monday, I'm taking the whole shaft for balance with the couplings attached, as I said before, I can't think of a different way even Jaguar can have done this? Apparently, the workshop I usually use can't fit the driveshaft on his machine to balance it while the couplings are on, so it has to be sent away to a specialist that will take 3 days (sounds like lots of cash doesn't it?)

One more question: Is there any information regarding rotation direction of the Jurid couplings? I didn't notice anything written on either of the 2 new ones?

If the above doesn't stop the problem after refitting, then it's a case of Carnival Kid's idea and have it on a lift where I can 'drive' it while someone takes a look underneath, I think I may be like you Carnival Kid, I got no hair either but mine is due to age, not the car... lol. I will update after refitting, hopefully either of you might have an answer re the rotation question before I refit it.
Paul

 

The Jaguar Parts Catalogue shows the locknuts as NV112051J and the JaguarClassicParts website shows them to be for the propshaft and, in the case of XJ6, also mention Jurid coupling so the part number should be correct. However, there seems to be some confusion about this part. I recently ordered 6 coupling nuts from Barratt (as p/n NV112051J) and what I received was 2 correct nuts and the other 4 were smaller nyloc nuts with UNF thread size. They are currently sending me the 4 correct nuts in replacement.

Jurid Couplings - orientation of the Jurid coupling does not matter as long as the arrows are aligned correctly (as in your pictures).

I just found a TSB related to the vibration (attached). This covers sedans from MY1995 - on meaning X308 as well. It shows checking of the propshaft horizontal alignment and states that it should be straight (no deliberate horizontal offset should be applied). A good advice contained in the TSB is to test with different (rotational) positions of the coupling - moving it by 120 deg. in relation to the diff. pinion flange (and, I guess, the same can be tried with the front coupling - moving it by 120 deg. in relation to the gearbox output flange).

 

A couple more points:

While your propshaft is out, check the diff pinion dowel runout (as shown in the TSB).

I would also check the runout of the dowel on the gearbox output shaft. If the dowel is perhaps bent, you can get the output shaft separately:

 

M Stojanovic, I have another question. In the 2 pictures I posted showing each Jurid on the end of the driveshaft, in the right side picture (ie. the Diff end) have I got the coupling the right way? Should the end of the driveshaft be the 'drive' flange with the thicker coupling arrow pointing to it, or with the thicker coupling arrow pointing to the Diff input shaft as in the picture? I see it as the end of the driveshaft being the 'drive' which means the Jurid should be fitted with the thicker part of the coupling to the driveshaft, am I wrong?

I believe the gearbox end is the right way, but I am doubting I have the diff end the right way, as the end of the driveshaft 'drives' the Diff! What's your take on this Carnival Kid?

Hope you can help hear...
Paul

 

You have positioned the couplings correctly, the arrows (their thin sides) pointing at the fingers of the flanges at both, the gearbox and the diff, ends. This can also be verified by looking at how, during forward car motion, the power is transmitted from the gearbox flange to the front prop flange and then from the rear prop flange to the diff flange. I have marked this on your pictures and it can be seen that the power (blue arrow) is, at both ends, correctly transmitted through the thicker sections of the couplings.

 

Hi Paul,

Didn't I already recommend checking about the bolts, washers and nuts and having the propshaft balanced together with the couplings a few weeks ago in the old thread?!
Anyways I​​​'m very happy that you were able to track down the potential cause of the vibration. So you'll hopefully enjoy the smooth and subtle ride of your car soon again :-)

Cheers, Alexander
​​​​​​

 

I just noticed that the coupling nuts shown on your pictures appear to be nyloc nuts (correct me if I am wrong). Nyloc nuts are normally not used on the coupling bolts (their jamming is not strong enough for the application) but all-steel jam nuts like these (Jaguar p/n NV112051J I recently bought):


Alternatively, these can be used (Jaguar p/n NV112041LP)

 

M Stojanovic, please forgive me, I'm still not feeling happy the way I have my couplings on. I am presuming the picture you sent me in post #3 was the back of your gearbox? In that picture the thicker part of the coupling is facing the gearbox flange, where mine (as below) is facing the shaft. Even though the thicker part arrow on mine is pointing to a flange, it's pointing to the shaft flange rather than the gearbox flange as shown in your picture?


This is the gearbox end of my shaft, the thicker part is facing the shaft not the gearbox?

I am a little concerned now as I have sent the shaft for balance, and if I have the coupling(s) wrong it will be a wasted effort. Also, at the Diff end, doesn't the shaft become the driving force, and therefore the thicker part of the coupling should face the shaft? I am really confused over this, am I 'over thinking' this?
Paul

 

XJK2014_de Yes, you were bang on about using all the same bolts, nuts, and washers because of the weight factors. You were also right about having the shaft balanced with the couplings attached, though my guy can't do it as the shaft wont fit on his machine with the couplings on, so we had to source it out to another engineering company. When I mentioned about someone telling me to balance with the couplings on in post #1, it was your good self I was referring to

I did receive all the fixings from Jaguar, but they sent me 8mm nyloc nuts instead of 12mm, so I telephoned them. I happened to be able to speak to someone who had worked there since 1995, and was involved with the building of X308's from 1997, he gave me a part number and eventually they sent me 12mm nyloc nuts, so I assumed they were correct and fitted them.

Hopefully, I will get the couplings on correctly too, THEN i might get the smooth driving experience lol.

Many thanks for your reply.
Paul

 

Your arrow (moulded in rubber) is correctly pointing at the propshaft flange finger and so are the other two not seen on the picture. The arrows at the three free (at the moment) holes in the coupling, which correspond to to the gearbox flange, are in opposite orientation to the arrows pointing at the prop flange so they will also correctly point at the gearbox flange fingers.

 

Here's a drawing of complete propshaft by looking at which you can easily verify the correctness of your installation.

 

Hi, sorry I haven't been back in touch for a while, not been well again unfortunately. (Again unfortunately) we've been hit in the UK with extremely high winds, and as I have no access to a lift working under the car in axle stands is not a safe way to spend any amount of time!

However, firstly I want to apologise to M Stojanovic for my ignorance at realising what was meant by the thicker part of the Jurid coupling in relation to the drive flanges, I stupidly thought you were referring to the thicker part 'width-wise' from the moulding line that goes all the way round! I now see from the picture above exactly what you meant. Why I was thinking wrongly is down to my usual excuse... age and ignorance!

Anyway, so far I have the shaft on and currently refitting an exhaust, I decided to fit new as the old was getting a little rusty and tired looking. I also managed to raise the prop-shaft centre bearing very slightly as you suggested, I added one of the spare thin spacers and made sure the bearing collar wasn't touching any part of the transmission tunnel, and was bang centred, it was a little tight but when all was tightened up there was about a 1.5 mm clearance. Once done, I will hopefully have a smooth driving experience, I will report back once the weather has let up and I can get it finished and back on the floor.
Paul

 

Hi to both Carnival Kid and M Stojanovic. Got the prop back on but now having another 'daft' problem, have posted a new thread about it. Another fact the book doesn't tell you is which way the front exhaust muffler goes on, with the pipes coming out of the back of the front muffler pointing slightly up, or down? Remember mine pointing down when I had to hammer it off (with a very heavy hammer and bits of wood to protect the muffler).

Trying to put it back on the same way but it is so tight. As the book says "slide the exhaust backwards and forwards" I'm beginning to think I have it the wrong way? (The pipes coming out of the back of the front muffler are facing down). Any ideas?
Paul

 

I hope you have no more vibration.

Currently, my propshaft is also out (the transmission too) as I am replacing the rear crank seal and the seal-washer on the oil gallery plug above the crank - had quite a bit of engine oil leak, probably more from the gallery plug as it was slightly more than finger tight. When I inspected the guibo bolts, nuts and washers, I found that, in total, 12 of the washers had smaller OD and were thinner than the other 12 washers. I believe that the smaller washers go between the bolt heads and the flange fingers and the larger washers go between the nuts and the guibo (acting as fender washers against the rubber). Strange installation by Jaguar, inviting vibration when, during guibo replacement, the washers are mixed-up. The weight difference between the smaller and larger washers does not matter if they are evenly spread at each guibo (smaller at all bolt heads, larger at all nuts). However, the PO who replaced both guibos (of course) mixed the washers up and installed them in random combinations. When I weighed the bolt/nut/washer assemblies, kept together as I removed them, I had a case (at each guibo) that one of the bolt/nut/washer assembles that connect the propshaft to the guibo was 10 grams heavier than the other two assemblies because it had two large washers on it and the other two bolts had smaller washers. 10 grams is huge when compared to very high precision to which the propshafts are balanced (to less than 1 gram, I guess). This explains why I had high frequency vibration (buzz) when I exceeded 90 mph.

 

So it seems you've had a similar problem as I had? Well I can safely say that I know of no-one else that will know about this problem more than yourself, your help has been invaluable to me . The jaguarclassicparts site only shows just the one washer fitted to the head of the bolt and the same to the nut, but I guess (like you say) it doesn't matter that much so long as they're all equal all the way round. BTW. the people that balanced my prop-shaft said they've had quite a few to balance from X308s and that balancing with the couplings on is the way Jaguar did it originally, so it seems I did the right thing? I also managed to raise it a little when refitting as you suggested by adding an extra thinner spacer to the mounting, it just to say clears the tunnel, it's pretty easy to remove if it's a problem though.

Though mine is all back together, I had a bit of a disaster! I started the car, started first time but for some reason had a cylinder or 2 not firing and cut out after around 20 seconds or so (it hasn't been started for nearly 2 weeks). I tried starting it again but it only fired, nothing else. The battery wasn't strong enough to keep on turning so I tried jump starting, guess what, it now seems I have the bore wash problem again, because of it starting briefly then stopping. Now when spinning over it sounds very similar to what it did before when I had bore wash. That was when I had never heard of the problem, and I followed what everyone told me and fixed it with a little oil down each bore of one bank. Since then I've been very careful to make sure the car was warm before switching off. I started removing the plugs on the left bank then I lost the light, so tomorrow I will put a little oil down each bore and see if I can get it going, I have the battery on charge and will leave that overnight so it's strong. I only hope it doesn't blow either of the 'knock sensors' again like last time!

The sooner I can afford a 4.0 with steel liners, instead of the 3.2 with nikasil, the better. I have read that a 4.0 NA engine will work if you use the Cam cogs from the 3.2 instead of the VVT ones fitted to the 4.0, then drill and tap the VVT oil holes and fit a bolt with a sealing washer? After that you also need to use the 3.2 Cam covers. Apparently, there's no need to change the ECU, the TB, or anything else, and it drives better on the 3.2 differential. Have you had any experience of this or heard of it before? It seems that it would be a useful change as my 3.2 does seem a little 'flat' after 130k miles?

So here I am, done all that work and can't tell if it will run smooth as it doesn't 'run' at all lol. I will resolve this, I am determined! Let me know how you get on with fixing the crank oil seal, and if swapping out the washers cleans up the high frequency vibration you have.
Paul

 

I have not done engine swap but I have installed cylinder heads from a 4.0 NA on my 4.0 SC engine (Daimler Super V8). I plugged the VVT oil holes in practically the same way as done in the factory, using special rivets and a heavy duty rivet gun:

Avdel Avseal II 02961-00810 High Pressure Series Blind Sealing Plug; M8 Diameter (had to buy a pack of 25)


With regard to my propshaft, I will be using all new bolts, nuts and washers (washers are all the same size). The strange thing was that Jaguar messed-up the part number for the nuts (NV112051J, M12 x 1.75 Grade 10, suitable for Grade 10.9 bolts) and now supply some smaller nyloc nuts in size 3/8-24 UNF. Barratt (from whom I bought the nuts) are currently checking with Jaguar what happened here. Meanwhile, I got the correct nuts from BelMetric at https://www.belmetric.com/coarse-c-3...3ddqlrc52aj0m2.

I also decided to buy a vibration tester ( https://www.ebay.co.uk/itm/VM6360-Di...72.m2749.l2649 ) which I will use if, with the new hardware, I still have some buzzing/vibration and in-situ balance the propshaft myself using the old "two hose clamps method".