1997 940 2.3 M90 vibration/judder

[black t top]

Hi guys, last problem I'm trying to sort on the new 940. The car has done 116,000 miles.

There is a vibration that comes in (through the seat base not the column) at 50mph, gets particularly bad at 60mph and stays throughout the range, seems a bit better at 70+ but that's probably just the vibration being so quick it's blending together and being less noticable. car is smooth all the way up to 50mph.....vibration comes in around 2100 revs in 5th, if I drop to 4th gear it doesn't feel very noticable, but again, the revs are much higher so it might just feel smoother as it's all spinning faster.

The driveshaft has been removed, the center bearing and carrier checked for play and the last owner has replaced the universal joint. My local Volvo garage are suggesting replacing the complete driveshaft assembly to completely rule out the shaft. It feels like wheels out of balance, so I swapped the rears to the front to see if the vibration moved from coming through the seats to up the steering wheel, it didn't. Garage checked the engine mounts and they are fine.

There is also a judder when pulling away in 1st gear. Pulls away smoothly in 2nd. Judder is present when cold, goes away once hot/driven a bit. The judder has improved over the last 1000 miles, but still does it. If it's really cold like the last few days -7 it didn't judder at all. I'm assuming this car has a DMF and the DMF is faulty.....given it's not horrific anymore should I just hold off till it starts slipping before changing it? Could the DMF cause the driveline vibration?

I've recently had the turbo gaskets and manifold gaskets all replaced, the garage told me that someone had recently been in there and a lot of the nuts were loose, causing the exhaust blow.....what would happen if a HPT was fitted to a LPT car......would this cause a vibration at 50mph plus, due to the fuel/air mix being wrong, bit like incorrect spark timing would? Just a thought as I'm assuming the turbo is the original LPT one, but have no way to check.

So......any suggestions aside from just replacing the DMF and Propshaft assembly?

[Laird Scooby]

If you dip the clutch at 60mph in 5th, does the vibration disappear?

Also i wouldn't rule out the centre bearing/carrier, i recently had to replace the one on mine (albeit with a lot more miles than yours) with a new one due to exactly the same symptoms. When the bearing was off the car, it felt and sounded fine but once it was on the car and had been running a while (strangely mine didn't do it cold either) it started to get noisy and vibrate. I also found it doesn't always sit in its "vibration free" position when first refitted, had to loosen the bolts very slightly and take it round the block then retighten them after to get it completely vibration free.

I still have a very small amount of vibration from a worn diff but nothing like it was.

Something else that can cause vibration is the dust cover on the back end of the centre bearing, it's basically a convoluted rubber tube that is meant to protect the centre bearing from dust and other stuff (the bearing is double sealed so it's probably overkill on Volvos part) and if there are any splits, cuts or bits missing from this cover it will vibrate.

Also do you carry a lot of load in your boot? If not are your rear springs and/or Nivomats worn? If so the diff will be making the wrong angle with the propshaft causing vibration, the guys that go in for lowering have found ways round this but i went for the simple standard springs/shocks conversion, gained over an inch of ride height back and lost some vibration - at that point i hadn't found the centre bearing, gearbox output shaft bearing (mine's auto) and a couple of other things.

***EDIT*** You say the garage checked the engine mounts - did they also check the gearbox mount?

[Steve940estate]

It sounds like the big vibration you are getting is from the propshaft. If a joint has been changed was it balanced afterwards ? Sometimes just bolting the propshaft back in with it twisted 180 degrees can cause a problem. I think you will also have the rubber coupling at the front end. If you check by disengaging the clutch at speed as suggested and it still does it, there is a good chance it's propshaft or axle related.

As you are getting judder from the clutch there is a good chance it is worn or getting oil on it. It could be the DMF although I haven't read about people having the same problems other manufacturers have had where they go all loose and start rattling

[Rversteeg]

Drive shaft vibration and judder when pulling away are probably not directly related.
https://www.volvoforums.org.uk/showt...ight=vibration

Drive shaft vibrations after replacing the prop shaft bearing are quite common unfortunately. It seems like when you take the drive shaft of and pull it apart you introduce new unbalances somewhere. I am struggling with the same thing right now. I have tried rubber dampeners underneath the bearing and bearing plate to give it more flexibility, but it did not make much difference. I am now planning to check the alignement, to try different bearing height positions, rotate the flange connection that has been loose by 180°. I am not ready yet for replacing the complete drive shaft.

[black t top]

Thanks all for the input, yes the gearbox mount was also checked and got the ok at the garage.

Center bearing carrier height, never considered that, I thought it would have been set in place at a fixed point, I might try slackening the bolts slightly and doing like Laird Scooby, run it round the block then re-tighten them.

No weight in the boot, doesn't carry heavy loads, aside from a slightly fat border collie haha! Rear springs are new(ish).

Dipping the clutch at 60 or while it's vibrating makes no difference, so I "think" the problem is in the shaft/axle/rear wheels (although I switched them for the fronts and no difference).

I was considering swapping the shaft from our 98 car into the 97 car to see if it fixes it, but I'm wary touching the 98 car as it runs silently and vibration free.

Wish the weather was better and I could do some work on the car myself, 2 940's and a Trans-Am and every time I get a day off it's either chucking it down or baltic!

[Rversteeg]

Don't touch the 98 prop shaft if it is silent and vibration free!

[Laird Scooby]

Someone has suggested rotating the propshaft through 180 deg on the diff flange, i'd like to suggest 90 deg increments - might take longer to find the vibration free point (if that is the cause) but the first answer won't be "all or nothing" as it would be with 180 deg rotation.

Also if your other car doesn't have a vibrating prop, i'd LEAVE IT THE HELL ALONE!!!!!

Put another way, if it ain't broke, don't fix it!

You could end up with both cars vibrating nastily!

[Laird Scooby]

Someone has suggested rotating the propshaft through 180 deg on the diff flange, i'd like to suggest 90 deg increments - might take longer to find the vibration free point (if that is the cause) but the first answer won't be "all or nothing" as it would be with 180 deg rotation.

Also if your other car doesn't have a vibrating prop, i'd LEAVE IT THE HELL ALONE!!!!!

Put another way, if it ain't broke, don't fix it!

You could end up with both cars vibrating nastily!

*** EDIT *** If you go for the roate through 90 deg, road test, repeat until vibration fee, make a mark across both the prop and diff flanges with Tipp-Ex or similar so you know where you started. When you're done, scrub them off and then make a new mark for future reference.

[mjk164]

Black T top.
You say that the prop shaft has been removed for some checks etc. It is essential that the front section of the shaft must be kept in the same alignment with the back section. On my 1993 960, the yokes of the universals at the centre bearing have markings on them (arrows marked on the shaft) from manufacture which indicates the correct alignment. You may have to clean off paint or any dirt which has accumulated on the yokes to see them. They could easily be one or two yoke splines "out" of original alignment; but the whole shaft would have been balanced to proper alignment and marked in the factory. On mine, I have replaced the center bearing and one U/J and, put back together with the alignment marks set up, it was and still is in perfect balance. I recommend you put the car up on jacks or whatever, get underneath and try to see the marks; I think that's where your problem is.

[Clan]

You need to put the rear of the car on axle stands under the axle , leave the rear wheels off and run the car up in top gear , run the engine up to what ever speed you got the vibration at and see if you can reproduce it ...
If you parted the two prop shaft halves and re assembled them with no though as to their orientation to each other then that is likely the problem . As said above there is an arrow stamped on each shaft near the centre joint which should align with each other , probably covered with underseal !