Another noise problem

[Danjwilko]

Well another problem has reared its nice little head grr, basically I changed a set of Michelin latitude sport 3 tyres which were almost down to the 2mm mark ( grip was ok but for winter and wet weather I wanted new rubber) they were a bit noisy being fairly worn and hummed/droned quite a bit.

So as posted previously I picked up a set of quatrac pros and had them fitted, sooo much quieter or so I thought until I let off the throttle half a second latter I'm met with a rumble/grating droning sound. Sort of like driving along a concrete road bit with rubbing discs only way I can describe it.

I jacked the xc up span the rear wheels and found the disc covers had been bent so we're touching the discs causing a constant grating noise not the on off one I'm getting. Tyre place had rested the wheels on the discs when putting them on.

Bearings checked whilst off the deck and found the rear diff to have a bit of light noise so changed the fluid.

The rumble/grinding/drone still persists the only other thing I tried was shifting into neutral noise instantly disappears, same if I brake.

I've since noticed the noise appears predominantly around 60mph letting off throttle to about 50, then again if I lm hovering on the gas around 30mph but you can only really hear it if it down shifts automatically to 3rd it starts rumbling/grinding. It's like any take up of drive stops the noise and coasting so to speak it returns. I can't tell if it does it on heavy throttle due to engine noise but it definitely seems to go once you ease the throttle to get back up to speed.

Anyone have any rough ideas what to check? Or had any experience of similar?

I've had diff failure and bearing failure before on both 4x4s and BMW's so I'm at a bit of a loss with this one.

Sorry for the long post, I know vague descriptions don't help lol. If I can record it doing it Il post it up.

Any input would be appreciated hoping it's not the trans, would be sods law buy all the fluid and filters to do the trans, diffs and aoc if it is.
Cheers all

[Danjwilko]

Well after taking it out again driving it down the aerodrome near us think I've finally managed to pinpoint the noise a bit better, before I couldn't hear anything whilst accelerating, with the smooth surface of the old runway I could here the drone/ grating noise at 50mph with gentle acceleration. Got it up to 60 and let the throttle off and it starts around half a second later at at least twice the volume.
Once down to 50mph nothing until I accelerate gently again. Seems to be louder chatter more in 4th gear at 50mph than 5th gear at 50 but still the same noise and seems to be speed relative.

Only bit that baffles me is it does the noise on slight throttle at 30 in 3rd but not if you let the throttle off.

Noise is loudest at 60mph letting off the throttle, flick into neutral and I get nothing no noise what so ever.

So that would eliminate bearings theoretically tryes etc, any rotation to the rear drive train so I've got propshaft CV joints, center support bearing, output bearing on the trans and bevel gear and potentially rear diff and or haldex.

Not sure if I'd still get the noise if it was the diff or not as it's still moving during drive in neutral just not the input bearing.

I've got the front right engine mount to change as it moving a lot. So if I get a chance Il drop the propshaft, check the joints and center bearing.
I did read that it may or may not have a vibration damper fitted aswell fussing from the quick look I'm guessing that it's got them. Photos attached.

[S60D5-185]

That front CV joint shouldn't have oil or grease on it.

Have you grasped the propshaft at the front and tried to shake it sideways as the bearing supporting that front flange can wear allowing oil past the pinion seal.

If all good, the CV joint itself could be suspect . It should be bone dry .
CV joint is about £50 but count the spline numbers very carefully if ordering a new one

[Danjwilko]

That's not grease it was penetration spray, preparing to drop the prop, everything was bone dry, no signs of any leaks whatsoever. So I'm struggling to find anything and being an intermittent noise it's hard to pinpoint. Still couldn't undo the bolts so I'm going to give it a thorough soaking and see if I can crack them off.

[Danjwilko]

Should have mentioned the prop has zero movement side to side etc slight bit of flex in the centre near the support bearing. However I can turn it around 45 degrees total back and forth, which seemed a lot of I'm honest however I've limited experience of the AWD systems only regular transfer case with diff locks etc. Old school landys.

[Danjwilko]

Didn't get chance to drop the propshaft in the end however I changed out the front drivers side engine mount as that had dropped by about 10mm loads less vibrations during drive, noise however is still there so it's not mount related as all have been changed, I did notice the bevel gear housing has a old/slow leak so maybe that causing the noise. Il drain and top up with new fluid see if it makes a difference. It probably needs doing anyway judging by the colour of the rear diff fluid.

[kiwiV8]

Also try disable Haldex and drive around, mine are loud with haldex disabled. Other symptoms are similar. Droning loudest when coasting between 80km/hr - 50km/hr. Wondering if I can lube the cv joint without dropping prop shaft.. if so then might try that first.

[Danjwilko]

You are a legend, didn't think to switch the DTC off switch it off and no noise what so ever really weird, so would that be the haldex unit itself? No noise in neutral, or with DTC off switch it on its droning/grinding away on coasting usually in 4th guessing from the rpm range from about 50-40mph, chattering away whilst crusing at 30-40mph light throttle again switch DTC off nothing.
Any input appreciated.

Cheers guys.

[binty]

Sounds similar to a vibration damper.

I have had mine checked by a Volvo master technician who advised that Volvo did and did not fit vibration dampers to the propshaft at various stages of manufacture. (almost at random it seems).
The symptom is what he describes as a 'drilling' sound on coasting.
Volvo do a conversion to add the damper for about £350, and fitted it to those cars under warranty that had issues, but not out of warranty.
You could get a second hand propshaft with one fitted. (apparently it is like a thick rubber bit at the rear end of the prop shaft).
May be worth a look to see if yours has the damper or not.

[Danjwilko]

I'm pretty sure it has the dampers fitted, but il double check, I've got the oil and filter for the haldex/AOC on order as I'm pretty sure it's not been changed, and the gearbox oil too (changing all the fluids slowly but surely).

To do list:

Check if dampers are fitted( sure they are).
Drop the prop shaft check cvs
Haldex filter,oil
Gearbox oil change,
Arb bush.
Front drop links
Big job all the rocker arms and the hydraulic tappets.
Discs and pads all round.

Jobs done:
All engine mounts.
Aux belt + tensioner
Rear diff fluid.
Rear hand brake shoes cleaned up (sticking slightly).

Side note all the engine mounts were changed as both the bottom ones had gone, was recommend to change the rhs one due to vibration and possibly causing the grinding noise. Obviously didn't do squat.

And the rear diff oil was more if a precaution as I didn't think it was that but the new oil made zero difference so guessing it's not the diff.

Il have a look at the weekend and get some jobs ticked off and get back to you guys.