Yeti 4x4 rear noise driving me mad.

[Benh]

Hello there,

 

 I’ve ever been on a forum before so please bear with me.

 

I really need some help before I go to the dealer.

 

I have a 2014 Skoda Yeti 2.0D 140 DSG 4x4 approx 45k miles.

 

The problem I’ve had since buying it 1 year ago with 32k miles is a hollow sort of  humming/howling (can't think of better words to describe it) from the rear when cruising at speeds above 55-60mph in any gear that gets louder the faster I go, however If I apply power it instantly stops, cruise or remove power and its very noticeable, I can literally play it like an instrument using the throttle.

 

I’ve had the wheel bearings checked and they are OK, Cornering makes no difference to the noise.

 

The Haldex oil and filter got changed 6 months ago, it made no difference at all.

 

Its been 4 wheel aligned and had 4 new tyres, again no difference.

 

Im just wondering if anybody else has had this before? The most annoying thing is that my old 2010 Yeti had exactly the same issue that even Skoda could not solve.

 

Im an ex mechanic but with only five years experience before falling ill (poor memory is just a small part of it) but for the life of me I can't work this one out. 

 

I've thought of Prop bearing and Diff but at that milage?

 

Any ideas/help would be very much appreciated

 

Many thanks in advance

[J.R.]

Yes, had and still have exactly your problem.

 

I will bet a pound to a piece of **** that whoever did the Haldex fluid change made the frequent but never admitted mistake of draining your diff oil by mistake, its position at the bottom of the casing directly under the Haldx filler is what throws people.

 

They will then have removed the pump unit losing some fluid in doing so which they will have just thought was residual, on refilling they will have found that they put less in than the specified quantity or may even have overfilled.

 

They will have left you with a dry axle and possibly an overfilled Haldex coupling, if you get under and look at what drain plugs look to have been removed & where there are oil stains you can be fairly sure.

 

I drove about 300 miles and it was only the last 100 at high speed on the motorway carrying a very heavy load (overloaded) that I stsrted to hear the noise that you have, I drained out the tiny bit of diff oil remaining which was black & carbonised, flushed it through with paraffin, ran it on axle stands with 50/50 diff oil & paraffin which came out black, refilled with diff oil, drove for a week & drained & refilled again, I am left with a slight noise but only because I know what I am looking for and am waiting for the day that the diff gives up for good, I am amazed that it lasted as long as it did and came out relatively unscathed but damage will have been done.

 

Dont go thinking that it cant be the case on yours after 6 months have elapsed, the rear diffs are incredibly robust and do very little work, there are multiple reports of this happening to people after a garage has serviced the Haldex coupling, one persons diff broke through the casing 6 months afterwards and they had not heard any noise beforehand, perhaps they did not have mechanical sympathy but when the casing broke no oil leaked out.

 

Chack yours ASAP!

[J.R.]

Just read again that teh nosie was present before the Haldex service, maybe the damage was done the time before?

[Urrell]

Could it be exhaust the out of alignment thrumming on the body.

[J.R.]

There is also the relative lack of soundproofing in the Yeti to take into account, in the Octavia the rear seat squabs sit flat & tight to the floor above the fuel tank and provide a very effective sound barrier, with the roller blind deployed the rear compartment is virtually sealed off from the cabin.

 

On the Yeti the Varioflex seating (or whatever the name is) sits up above the floor & there is only a thinly carpetted rigid plastic panel underneath.

 

I know when my diff was dry of oil and at an elevated temp on the motorway journey I could play a tune in exactly the same way as the OP, after the flushing and fresh oil its still there but barely perceptible & only because I am attuned to it, it only does it in gear above 60mph and is for the time being at least quieter on the over-run or coasting in neutral.

 

The optimist in me is now questioning if what remains is tyre noise as it changes frequency when I drive over the French equivalent of rumblestrips which are simply a solid line composed of 5 or 6 individual smaller stripes, it makes the tyres sing and its like my transmission noise changes key, I'm hoping that it will either go away or get worse when I change to winter tyres either os which will tell me that its tyre & not transmission noise and I have had a very lucky escape.

[widdershins]

It might also be the rubber coupling between the driveshaft and the haldex.  I think it's called something like a Guibo (not sure if that's the right speeling) but it has rubber bits fixed into it (glued?) which can slowly separate from the metal casing over time.  There's a thread on here somewhere with photos of it and the signs to look for if it's failing.

[aka_pseudonym]

I'd certainly follow up widdershins post above this.  I had something similar although I must admit it was sort of opposite as it came on when I applied power and went away when I backed off.  It was discovered when it went for its MOT by the excellent old school mechanic at the garage I use.  They are a poor components he said and fail on lots of VAG cars with four wheel drive.  Expensive part for what it is - nearly £200 as I recall.  Certainly worth a look.  Looks like this.

[Ootohere]

http://briskoda.net/forums/topic/481392-4x4-rear-propshaft-coupling-damper

 

 

 

Edited 17 September, 2020 by e-Roottoot

[Benh]

Thanks for your replies.

 

I changed the Haldex fluid when I bought it at 32k after my last yeti's failed at 76k, I bought it at 50k and it turned out it hadn't been done by the main dealer in Dublin at 40k! it was screwed!

It was definitely the Haldex I changed and not the diff, yesterday I did the Haldex again and the rear Diff, both drained almost 1ltr each, diff was crystal clear and Haldex wasn't much worse, absolutely no difference to the noise though.

 

Today we went to Clumber park so I got the wife to drive while I sat in the rear and my god is it noisy back there! sticking my head in the boot it's definitely the rear,  I think I'll get a load of sound proofing and do what I had to do in my old one, it definitely reduced the noise one hell of a lot.

 

As for the big expensive round thing it does actually have some cracking in it but only slight, definitely worth keeping my eye on! 

[J.R.]

Glad to hear that!

 

I have made a variofloor and filled every cc of volume with "essential" junk which must go some way to reducing the noise, with the rear seats removed or tilted forwards the loading height is about 4" above the carpet & useless piece of plastic above the fuel tank which is where the noise must be getting through so I could effectively fill the 4" gap under the seats with sound insulation as long as it does not get in the way of the seat release a slide mechanisms, I am going to fill the void initially with blankets or something to see if it makes a difference and will then create something permanent out of extruded foam, its a job I need to do anyway to create a sleeping platform.

 

If I can silence the noise I might be able to forget about it!

[J.R.]

Wishfull thinking, just looked & I might be able to get a 20mm insulation sheet in there but with several cut outs, nothing thicker than that; will see if its worth doing after the blankets test

[Benh]

My thoughts exactly! If it's quieter I won't get so peeved off with it!

I've just received 36  10mm foam insulation sheats and a roll of 100mm polyester insulation, I'll be stripping the rear interior out and tackling it next week! Fingers crossed it'll do some good! 

[tintinandcharlie]

Hi Benh.

Did you ever get to the bottom of this noise? I seem to have the same thing going on. 

T

[Benh]

Unfortunately not, in the end I soundproofed outside under the wheel arches behind the plastic guards, under the floor protectors, behind the exhaust guards down the center, then did exactly the same on the inside, made a huge difference to the whine but also reduced the tyre noise a lot! 

[tintinandcharlie]

On 04/04/2021 at 22:41, Benh said:

Unfortunately not, in the end I soundproofed outside under the wheel arches behind the plastic guards, under the floor protectors, behind the exhaust guards down the center, then did exactly the same on the inside, made a huge difference to the whine but also reduced the tyre noise a lot! 

Ok, thanks for the update.