Hi guys and girls - Long time Skoda owner, first time poster !

On my 3rd Skoda now - had 2009 Scout, 2021 Karoq and now a 2015 Scout 2.0 Diesel manual.

I am chasing a drone from rear of the car, and am seeking opinions following my unsuccessful forum searches on this topic.

Car is 2015 model, 60K miles, 6 spd manual, 2.0 TD.  Oh, and Denim Blue, as I know such things are critical!  I am second owner, and car is fitted with trailer hitch - no idea what it was used for, or how often.

There is a drone from rear of the car, most noticeable at 65mph - 75mph. When you lift off the throttle, it is most pronounced.

Car had 1 odd tyre on NSR which I have replaced to match remaining 3. Have also had new rear wheel bearings fitted NSR and OSR. New F and R brake discs and pads. Car recently had a service, including full Haldex service. I think the diff noise was masked by the worn NSR tyre I replaced. All U-joints checked - no excess play or stiffness in any of these.

 

I can only think the differential itself is to blame.

 

I was considering swapping diff fluid as a possible next step - this would allow inspection of the old fluid, and possible swapping to a slightly heavier weight fluid.

Are the differentials on the Scout a weak point, i.e. is this a common fault ?

Would welcome advice as to the next course of action to take.

Thanks in advance !

 

Chris

Welcome.

The rear diff is not a weak point or a common problem.

No harm in changing the oil.

 

Check the Prop shaft Donut,s condition.

 

Hopefully no error was made with the Haldex Service and they drained it and not the Diff (That is sadly common.)  and a proper clean out was done.

Thanks for the input.

I am certain Haldex service was done 100%, as he is a specialist in VAG products, especially Audi and Skoda.

Will have a poke 'round this weekend when we get it up on his ramp, but we gave it a pretty thorough going over a week ago, looking for possible causes.

Underside of this car is as clean as the topside, so it was well-kept, but the trailer hitch has me pondering what they dragged around for 60K miles !

Dragging around for 60,000 miles might not be an issue for a rear diff.

 

The 3 -5 meters of reversing a boat / jetski on a trailer into the water, fresh or sea water and again to get the water craft out of the water is why a rear diff oil change can be 'simply clever' / common sense.

 

So if Wheel Bearing are ruled out and the Haldex is not an issue then maybe drain that rear diff and see how the oil looks. 

From my experience on a MkII Octavia 4x4 that's an issue with the rear propshaft doughnut.

 

My guess is it's loudest at about 2300rpm and actually occurs in all gears but is most noticeable in top when cruising on the motorway, gets louder under heavy load and can be 'driven through' such that it disappears at about 85mph?

 

If so Skoda will try and charge you about £800 for a whole new propshaft and then more on top for fitting it but the doughnuts are available separately for about £100 (they are common across the Octavia / A3 / A4 platform IIRC and some independent garages will have had experience of diagnosis and fitting them (albeit this is quite rare - the one I spoke to had only ever done a couple of A3's).

Edited 14 June, 20241 yr by skomaz

Skomaz, you must be psychic ! That is exactly the symptoms. I can 'drive through' the noise once I get 78-85mph. It's right around 65mph and in 6th that I hear it the most.

 

Will investigate this ASAP. Also think it might be worthwhile to change the diff fluid as it's probably the original. Belt and braces !

Thanks guys, appreciate the prompt input on this problem.

SOLVED !

 

Skomaz, you nailed it. Replaced rearmost propshaft coupling, and hey presto - no more noise !  

 

Thanks a million for the advice. 

36 minutes ago, SendInTheScout said:

SOLVED !

 

Skomaz, you nailed it. Replaced rearmost propshaft coupling, and hey presto - no more noise !  

 

Thanks a million for the advice. 

 

Excellent news...   Really chuffed you got it sorted!

My pal as a passenger today remarked on the diff drone, he asked me if I had M&S tyres on the rear.

 

I believe that mine is a result oif me driving it dry after making the filling mistake, I do have a new coupling but have yet to fit it because of the grief of moving the engine forward to allow removal, knowing that yours has been resolved by the replacement I will get on and change mine

 

Maybe there will be a second thankyou to Skomaz!

On 14/06/2024 at 15:18, SendInTheScout said:

Also think it might be worthwhile to change the diff fluid as it's probably the original.

 

No need from my experience, when I drained mine in error (the start of my self inflicted damage) what came out after 79k miles was as clean and clear as the day it had been filled in the factory, really impressive!

 

I cant say the same for the first and second flushing refills after I had driven 300 miles on autoroutes and A roads 200 of which towing but its testamant to the ruggedness of the diff that it did not seize and has done a further 60k miles albeit with noise/droning.

Perhaps I celebrated too early !

 

Although the persistent noise originally reported has now disappeared with replacement of rear prop shaft coupling, I notice now that if you get on the throttle in 5th, say around 65mph, the differential seems to drone when under that load. So I am now wondering if the original noise was masking this underlying noise. 

Short of a replacement diff, what might alleviate this noise ? And should I be worried, as under normal loads and speeds, it is now quiet...just moans when accelerating with a bit of oomph. 

Further info. After discussing with my mechanic, we noted that the drone typically happens once you firmly depress the accelerator - there is a 'click' felt through the pedal, which he said is a physical switch that tells ECU to give the driver all power available, and at the same time, engaging the Haldex coupling, and this is where the 'moan' is coming from - the car under full throttle also engaging 4WD. Does this theory sound plausible ?

Sounds feasible, probably could be confirmed with a diagnostic tool live data when it happens.

5 hours ago, SendInTheScout said:

After discussing with my mechanic, we noted that the drone typically happens once you firmly depress the accelerator - there is a 'click' felt through the pedal, which he said is a physical switch that tells ECU to give the driver all power available, and at the same time, engaging the Haldex coupling, and this is where the 'moan' is coming from - the car under full throttle also engaging 4WD. Does this theory sound plausible ?

 

Completely implausible, you have a manual transmission car (no kickdown) and the Haldex has a very intelligent controller that monitors wheel speeds, lateral acceleration, yaw angle, throttle position, steering wheel angle etc and even pre-emptively engages it anticipating wheelspin in certain situations, its laughable to think that its engaged by an accelerator pedal switch.

 

If you are happy with this mechanic then carry on using him but don't rely on him for advice, ask a drunken bloke in a pub instead!

Well, not sure what the next step should be. It drones/howls from around 65mph upward. Debating now about selling the car, as I fear diff replacement would be ££££. Shame, as the rest of it is in great nick.

I can try draining/replacing diff fluid - would 80/90W be OK, or perhaps a heavier weight worth a try ?

17 hours ago, SendInTheScout said:

I can try draining/replacing diff fluid - would 80/90W be OK, or perhaps a heavier weight worth a try ?

Be super super careful. Warning Will Robinson warning:

If you are changing the diff, make sure you don't accidently fill / drain the Haldex system. BTW - whilst I agree that the Diff probably does need new fluid, it will be the old oil in the Haldex system that needs changing that is causing the drone noise. Happened with my husbands 2015 Elegance 4x4. Haldex fluid AND screen was changed. Droning almost disappeared.

Varaderoguy, thanks for your reply. The Haldex fluid and filter were both changed about 6 months ago, same time as I replaced the driveshaft coupling, so I would think they would still be OK. Appreciate your head's up on not draining/filling at the wrong points on the diff ! I found photos showing the fill/drain plug, both requiring a 5mm hex key.

Any thoughts on what fluid (type and viscosity) would work best ?

You need some AUDI VW SEAT SKODA DIFFERENTIAL / AXLE OIL FLUID Part 1LITRE part no: G052539A2 for the diff.

There is (like everything on Briskoda) already a posting for this: https://www.briskoda.net/forums/topic/488831-any-guides-how-to-change-diff-oil/