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Discussion Starter · #1 ·
Hi guys,
I've had this S5 cab for a couple of years now and I love it! The amazing community here has turned me into an enthusiast and had me doing some mods which I think I am addicted to now! (car play install, smarttop one touch, rear ARB, carbon fibre intake, stage 2 mrc map)

Relatively new to awd systems and trying to work out what is causing this sound. Recently have noticed a low dull thumping / knocking sound while I'm driving / moving. This led me to believe it's something to do with wheels / bearings / diff / drive shafts?

Today I propped up the car on all 4 corners with axel stands and ran the car to try to simulate.
With the car in gear, the sound can be heard faintly and gets louder when accelerating. I got my dad to help and when he went round the car stopping each wheel - the sound stopped when he stopped the front near side wheel (even when I accelerated). The sound became more prominent when he stopped the other 3 (I assume because more power is delivered to the problem area?).

Took the wheel off; the brakes and disc seem to be fine and can't see any visible contact points which could cause the sound. Any ideas?
I noticed there was a bit of lateral play of the drive shaft between the 2 CV joints but only at a certain point while I was rotating the disc, is this normal? Could the spline be worn and cause this?
Any help would be appreciated
Thanks
Nick
 

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Nick mate, you tried to kill yer Dad??? This one is semi impossible to diagnose without standing next to your car. Take her to a local VAG specialist and get some expert opinion, if I were you!! And or fork out some dosh on a VCDS system and hook her up.
 

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Discussion Starter · #3 ·
Hahaha it was his idea! He assured me the diff should come into play and is safe.
Appreciate the reply, thanks, and yea without hearing it first hand can be difficult / impossible to diagnose. I personally think it's the drive shaft failing and will inspect a bit further at some point, just wanted to see if anyone else experienced anything similar? I wouldn't think there should be too much lateral movement in the axle for me to move by hand.
Not getting any error codes when hooked up to vcds (except the roof modules but that's because of the smarttop addition)
 

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Discussion Starter · #4 ·
Hi, just to provide an update....
It is the drivers side driveshaft that is causing the issue, a bit pricey but on the plus side of things doesn't look too hard to swap out.

Can anyone recommend where to get a good quality front driveshaft from?
 

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Hi, just to provide an update....
It is the drivers side driveshaft that is causing the issue, a bit pricey but on the plus side of things doesn't look too hard to swap out.

Can anyone recommend where to get a good quality front driveshaft from?
Genuine OEM from Latvia or Hungary via eBay, couple of high volume / reputable sellers there, fast shipping since you are UK and they FedEx them via France.
 

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Discussion Starter · #6 ·
Hi heylinTTnz,
Thank you for your reply. Was a little while ago, so I should update with my resolution.....

I did change the driveshaft and after researching, you are right, OEM is the best way to go or a reputable brand - I decided with SKF.

This did not resolve my issue unfortunately 😕
Which left me to believe it was either the diff or the wheel hub. I changed the hub and everything is now fine. I would never have thought it would be the hub / bearing, does not sound like how a worn bearing normally sounds (squealy). Could not feel it when turning / shaking the wheel but once the hub was off, could feel some grittiness.

So now I have a perfectly good, used driveshaft sitting in the garage. Any offers?
 

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Yeah hubs tend to hum when worn, not knock or thump. But glad you found the issue!
 
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