240 General: Rumble between 48mph and 55mph...driveshaft support bearing?

[AllHailKingVolvo]

Hi all,
My new (to me) Torslanda is a peach to drive. Absolutely lovely car. However the one thing I need to sort is a low, resonant rumble between 48mph and 55mph. It continues whether I'm on throttle or off, and dipping the clutch makes no difference either. It smooths out above 55mph and isn't noticeable below 48mph.

I also have a slight judder when pulling away in first if I'm too frisky on the throttle. It doesn't seem to be clutch related as when I deliberately slip the clutch in other gears, there is no judder and engagement is smooth.

All of this points to a worn driveshaft centre support bearing in my opinion...when I grab the driveshaft and give it a tug, it has perhaps 2/3rds of an inch of lateral play. I'm planning to take it into my local garage to have them change the bearing assembly and lubricate the UJs, but was wondering if anybody thinks I may be barking up the wrong tree before I commit to having the work done...I'm new to 240s as I've run 700/900 series cars until now, so have a bit to learn!

Thanks in advance for any advice!
Phil

[Volvo Jensen]

Hello,
2/3 of an inch (17mm) lateral movement sounds much to me (I take it You don't mean rotation on the driveshaft?), but I'm no expert.
From what you describe, and if the sound is the same in 4./5. gear and neutral, I'd guess the sound comes from the transmission, either outgoing axle in the gearbox, the differential, or somewhere between, as you suggested.

[AllHailKingVolvo]

Thanks VJ. It's booked in with my local garage on Friday, they take care of any work for me that requires getting the car in the air and are very well versed in older Volvos so I trust them to get it right.

It's definitely post-gearbox drive train, so will be either guibo/hardy disc, UJs, centre support bearing or diff. Hoping it's not the latter though as I don't fancy having to replace that!

[AllHailKingVolvo]

The plot thickens...the garage reckon the UJs, centre support bearing and output bearing are all fine, based on an afternoon of diagnostic probing yesterday. They suspect the pinion bearing in the diff has gone though so are investigating that this morning...hopefully not an outrageously expensive repair.

[Nicholas Lewin]

Hi Phil

I have had considerable transmission vibration problems - now resolved and which don't relate to your symptoms (so why reply you might ask!!)...

The back axle is pretty bombproof on a 240 (hence them being sought after for banger racing etc). What sort of mileage is your car and do you know anything about its history?

Some thoughts:
1 Have you checked the rear axle oil condition/level?
2 Your reference to 2/3 rds inch movement is quite a bit - the parts of the prop are readily available and cheap - they may be worth replacing
3 My car had had a clutch incorrectly installed. Installing a new clutch correctly resolved my transmission issues - could this be a factor with yours? (there is a specific Volvo alignment jig used installing a clutch on a 240)
4 Rear wheel bearings? Again cheap enough and not a massive job to replace

Good luck and let us know how you get on. Nick

[Clifford Pope]

Originally Posted by Nicholas Lewin

Your reference to 2/3 rds inch movement is quite a bit -

Is it? In the past I've replaced what I took to be a very soggy rubber doughnut and found that the new replacement was pretty wobbly too. 2/3 inch sounds quite modest based on my experience.
But what I think the loose mounting of the centre bearing does do is accentuate any small play in the other joints, by allowing resonance to develop as the shaft whips.

I would look very critically at the prop shaft joint by the axle flange. It's not just the twisting play in the needle bearing cups that matters, but end-float between each cross-pin and the ends of the caps.
If there is even a small amount of end-float then the joint can shift off-centre, and the vibration can build up, most noticeable at particular speeds or speed range. At low speed it's not very noticeable, at high speed it tends to centralise itself. I found that easing off the pedal and then applying power again sometimes shifted it and it would centralise itself, for a short while.

Apart from wear, it is very easy to assemble the joints incorrectly. Either a needle rollers is displaced unnoticed and gets trapped behind the cap, or one of the thin plasic cushions at the ends of the cross shaft is missing, or has been picked up with its fellow and both inserted at one end, putting the joint off-centre.

[AllHailKingVolvo]

Thanks gents. The car is a 1993 Torslanda with 120,000 miles on it, it was previously owned by an independent Volvo specialist in Leeds (P&R Cars) and I believe it was their courtesy car for some years before becoming the personal car of one of their founders, who subsequently sold it to me after retiring and downsizing to one car.

It's in very good condition and has obviously been meticulously looked after, has full history etc. The only issue is the rumble/vibration at speed and the judder when pulling away, which I can't help but feel are related.

There is no whine from the diff, I've certainly never had a rear axle issue with any of the 7/900 series cars I've owned, which is why I would be surprised if its a diff issue this time...I'll check the things you suggested, thankyou.

The garage are being a bit uncommunicative and useless about the issue, they've kept my car over the weekend without giving me any notice and I keep having to chase them for any updates...I think I'll collect it on Monday and sort it myself.

[BrianH]

All Hail Volvo. That is a good tag

No body has mentioned final drive bearing of the M47 gearbox.

When mine came out for a rebuild (at 552k miles) this bearing could be moved vertically up and down about quarter of an inch!!! I was amazed that it only vibrated but it did throw off exhaust pipes regularly fracturing the down pipe.

The non diagnosis was due to the gearbox supports having been renewed the garage missed it time and again as they could not get any movement from the bearing. You will have to loosen the flange to the prop to box and you might lose a little oil.


Good luck

BrianH 245 GL 1989 from new

[Nicholas Lewin]

DOH! Phil - I've just realised. Your rumble symptom is the same as the one that I had when I bought my car three years ago...

To cut a long story short (and until the gearbox was replaced which sorted the vibration and proved my point) no one would believe me and said that I should get used to driving an old car!

After 95k miles some of which had been motorway towing, 5th gear on my car was so worn that the splines were triangular on it's shaft. It wasn't noisy, but it set up a vibration very similar to what you describe. Either the gearbox had been excessively punished or possibly the oil level had been allowed to drop too low. A replacement 'box sorted that. And then the troubles with the clutch started (whole other story)

So...what happens in 4th between 48-55mph? I appreciate that the engine will be noisier, but do you get the same noise and/or vibration. Mr Volvo Jenson - did actually question this in his reply. If there is no vibration, you may just have a similar problem to the one that I had. This check will at least eliminate the gearbox from the equation

And as Brian H has also mentioned, the gearbox output bearing may be causing your vibration and/or judder...

Keep us posted. Nick

[AllHailKingVolvo]

Hi all,
An update...I went to visit the garage today and it turns out that it IS a worn out universal joint.

They struggled to get it to move or display any signs of wear or slop when in place on the car, but the output bearing, diff and CSB were all rock solid, so they investigated further and dropped the driveshaft out of the car, eventually finding that the rear UJ had around 3mm of play when removed and wiggled by hand on the bench...problem solved, thankfully!

The garage are taking delivery of the part from Volvo tomorrow and will hopefully have it back to me by the end of the day. I'm so relieved that it isn't the diff or gearbox...yet 😂