Rear diff noise?

[spartacus 68]

Typical. Just had a rear N/S wheel bearing teplaced on my A4 avant quattro prior to going on holiday and because my ears have been tuned to the tell tale whine of a bad bearing I have heard another noise.

Currently on holiday on the west coast, and coming back from the beach I can hear what can only be described as a 'wa wa wa' sound. It's quite a faint noise, but its louder if you're driving next to buildings as the noise seems to be exaggerated.

The rear diff is dry, no signs of leaks. The rear diff gear oil was changed at 115k. Currently at 146k. Any tell tale signs of a rear diff on its way out? Would it be worthwhile changing the oil again?

Any guides for identifying if there is an issue with the rear diff? Is it worth raising rear of car - spin wheels both ways, any tell tale sounds to listen for?

 

[Iceash]

Sure it's not the tyres? My rears have tooth saw'd make similar sound to bearing going. Very common on the vw audi scene.

 

[Iceash]

Passat Rear Tyres!!!!

 

[spartacus 68]

Thanks for the replies. I'll try switching the fronts over to see if that cancels the noise out. The rear diff is a solid bit of kit and I haven't read any issues with the A4, plenty on the A3, but that's the Haldex unit, so completely different set up.

 

[aragorn]

wa wa wa is typical wheel bearings?

rear diff just makes a whine, and its more noticeable at very low speeds IME.

 

[Bradderz_1988]

Yeah i currently have the wa wa wa from the n/s/r bearing and recently changed out the rear diff oil and n/s seal and has only started since the bearings give, im going to be doing all four bearings very soon as no history of them being done well what i can remember from the service history but its a piece of mind factor plus il be using genuine ones to cut out the hassle of them going again in a few months, also going to service the shafts too whilst im at it, aragorn were did you get your boots from when you did yours and how much ??

 

[spartacus 68]

Thanks. The O/S/R bearing was done in 2009 so could be culprit. That's £250 to change.

Bradderz_1988 - I've used GKN Driveline boots before. Nice kits and comes with everything you need. The rears on mine are original. The fronts probably get changed every 3 years at the first sign of deterioration.

 

[Kingfisher]

thought we had the same problem.
It was actually worn lower inner wishbone bushes causing play in the wishbones that lead to uneven wear on the rear tyres. MOT had perviously mentioned odd wear pattern on tyres ( nowhere near illegal depth).
New bushes new tyres ( needed by now ! ) no noise !

 

[spartacus 68]

Update. Jacked the car up tonight and there is a distict rumble from rear N/S wheel bearing. Rear O/S is quiet.

The N/S/R was changed less than a week ago by German specialist (not main dealer). Getting straight back to them to get it sorted. Has got progressively worse. They can't have bu**ered it up by putting it in the wrong way or damaging during installation? They must do these repairs day in day out.

 

[aragorn]

just a ****ty bearing, i've had a febi one fail inside a few weeks too.

Stick with big well known brands like SKF, FAG, Timken for decent quality parts.