Quattro / AWD Feeling in Front-End

[JWebb_C7_Comp]

Hey guys,

I have an uninformed question…

My A6 is 4 1/2 years and almost 50k miles. I have recently noticed that I’m feeling like the front end is “grabbing” the road when turning slowly - like in a parking lot.

When the car was much newer I didn’t really notice the front portion of the Quattro drive system working, and I’ve been noticing the same on my wife’s Q with roughly 70k miles.

Whereas both systems felt seamless when they were new, they’re feeling more like 4-wheel” drive now.

(1) do you all feel the same?

(2) should i be thinking about changing then fluid in front diff??

Or,

(3) am I crazy?


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[Spitfire007]

I have it too.
And it's getting worse and worse. Worse when turning a tight right from a stop.
People call it Quattro rumble, but I'm convinced something isn't right since the car was perfectly smooth until about 45000 miles.

I'll be doing the front and rear diffs and a trans service.
I also have two lower control arms leaking, so that might contribute, and apparently all engine and trans mounts are good.

So besides diffs and trans and control arms, I dunno where else to look.
Dealer said it was normal, which is a total fabrication.



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[JWebb_C7_Comp]

I’m curious if it’s transfer case related…leaving too much torque up-front when not needed


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[JWebb_C7_Comp]

I talked with my Indy, and they're doing a Center Diff fluid change. They're using Audi specific fluid. 1 hour labor plus fluid. I'll be out the door for less than $200. We'll see if it makes a difference after a couple weeks. According to the TSB on this issue, once the fluid is changed, it may take up to 600 miles to feel/hear the improvement. Apparently, this is a common "comfort issue" but rarely results in mechanical failures.

Having both front and rear differentials on my wife's Q7 along with the center done as well. Cost wont be but 1/2 of what the dealer quoted and, as you all know, getting these beasts on to (4) stands in your own, home garage without a scissor lift is really difficult as there's really no good front and/or rear center lift point.

Therefore, I'm "happy to pay" for maintenance that may also solve a nuisance issue We plan to keep both vehicles. Otherwise, i would not bother doing this myself or paying to have it done.

[Spitfire007]

By center diff, do you mean the transfer case?

I've been told different things: that the trans and transfer case/center diff share the same fluid.
I've also been told that they neither share, nor use (spec) the same fluid.

Does this mean we have:
Front diff
Transfer case/center diff,
Transmission
Rear diff



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[ANMS4]

?? When should we change this? I was thinking of doing the T-case and front and rear diff my next service ( 90k) Tranny was do at 80k

[JWebb_C7_Comp]

By center diff, do you mean the transfer case?

I've been told different things: that the trans and transfer case/center diff share the same fluid.
I've also been told that they neither share, nor use (spec) the same fluid.

Does this mean we have:
Front diff
Transfer case/center diff,
Transmission
Rear diff



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Yea, my language was sloppy. I mean Transfer Case. It’s attached to the ZF8 transmission. But the fluid is NOT the same as in the transmission. It’s an Audi specific fluid and, as I have read, does not “co-mingle” with the transmission fluid.

There are also two differentials. One front and one rear. If you have a sport rear diff, like I do, it has two separate fluids. One is a typical “gear oil” (75-90, I believe) and the other is more like a typical transmission fluid. But the cases are separate. Front differential uses a typical 75-90 fluid.

I hope the helps.


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[JWebb_C7_Comp]

?? When should we change this? I was thinking of doing the T-case and front and rear diff my next service ( 90k) Tranny was do at 80k

According to Audi, this is lifetime. Indy suggested 30-50k on differentials and the same on transfer case.

They don’t want to do the transmission, and suggested if I plan to do it I should take it to the dealer. Dealer said roughly $800 for that service. My older BMW was about $600 at dealer. That was a ZF6 transmission that was beaten and kept on going despite I didn’t change its fluid until 80k miles.

I haven’t decided if or when I’ll touch transmission. Mechanic buddy of mine used to say that automatic transmissions are amazing and should be left alone if they’re working….





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[Audpor911]

My A4 does this as well and I have upgraded Mugen Racing straight lower control arms. I strongly believe this is due to the front angled control arms bushings weakening. Simply change your lower control arms and provide feedback.

[Spitfire007]

My A4 does this as well and I have upgraded Mugen Racing straight lower control arms. I strongly believe this is due to the front angled control arms bushings weakening. Simply change your lower control arms and provide feedback.

I do know mine are leaking. I'll get it done soon and report back.


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[JWebb_C7_Comp]

According to Audi, this is lifetime. Indy suggested 30-50k on differentials and the same on transfer case.

They don’t want to do the transmission, and suggested if I plan to do it I should take it to the dealer. Dealer said roughly $800 for that service. My older BMW was about $600 at dealer. That was a ZF6 transmission that was beaten and kept on going despite I didn’t change its fluid until 80k miles.

I haven’t decided if or when I’ll touch transmission. Mechanic buddy of mine used to say that automatic transmissions are amazing and should be left alone if they’re working….





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I had the transfer case drained and filled Friday. After two days, there a big difference. Car feels much smoother in her tight turns, parking lot, etc….

perhaps $175 we’ll spent.


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[JWebb_C7_Comp]

Yea, my language was sloppy. I mean Transfer Case. It’s attached to the ZF8 transmission. But the fluid is NOT the same as in the transmission. It’s an Audi specific fluid and, as I have read, does not “co-mingle” with the transmission fluid.

There are also two differentials. One front and one rear. If you have a sport rear diff, like I do, it has two separate fluids. One is a typical “gear oil” (75-90, I believe) and the other is more like a typical transmission fluid. But the cases are separate. Front differential uses a typical 75-90 fluid.

I hope the helps.


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I had the transfer case drained and filled Friday. Car is much smoother in tight turns after just two days.


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[zyrofillica]

I had the transfer case drained and filled Friday. Car is much smoother in tight turns after just two days.


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The rear differential? Transfer case done meaning the front with the gearbox?

[JWebb_C7_Comp]

The rear differential? Transfer case done meaning the front with the gearbox?

I had transfer case only drained and filled. Think of two separate differentials (front and rear) a separate transmission and a separate transfer case, directing power to front and rear differentials. It’s that last component I had done.


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[Spitfire007]

I had transfer case only drained and filled. Think of two separate differentials (front and rear) a separate transmission and a separate transfer case, directing power to front and rear differentials. It’s that last component I had done.


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It's key to understand just how many separate systems there are.
My indy says they've never done a transfer case, much less front diff.
I may need to meet a different indy.
Dealer mentioned looking at a potential system replacement...wth...maybe a new diff or transfer case? The service advisor said over the phone they didn't believe in the lifetime fluid thing until they started working at Audi...go figure.

Maybe it's better to leave the system sealed, and if it starts to go bad, new fluid is just a temporary bandaid? Who knows...


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[A665]

It's key to understand just how many separate systems there are.
My indy says they've never done a transfer case, much less front diff.
I may need to meet a different indy.
Dealer mentioned looking at a potential system replacement...wth...maybe a new diff or transfer case? The service advisor said over the phone they didn't believe in the lifetime fluid thing until they started working at Audi...go figure.

Maybe it's better to leave the system sealed, and if it starts to go bad, new fluid is just a temporary bandaid? Who knows...

The indy and the dealer you're talking to are both woefully uneducated about these matters. As such, I would not trust them to rotate my car's tires, much less change its vital fluids. Find a shop with competent personnel.

[Spitfire007]

Not easy to find.
Dealer shop foreman drove with me and acknowledged its loud. Said he'd look up TSBs for the center diff, just like the Q5 has.

Tech drove it after and wrote in comments that it's normal, which I don't believe as it's getting worse.
They'll do a center diff fluid change for me for $420.
Trans around $1100.

Finding an Indy that's not as expensive is hard in PA.

If it keeps getting worse, I may keep it another year and ditch it instead of dumping money into it.
2016 A6 3.0T 74xxx miles



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[Akakios]

Not easy to find.
Dealer shop foreman drove with me and acknowledged its loud. Said he'd look up TSBs for the center diff, just like the Q5 has.

Tech drove it after and wrote in comments that it's normal, which I don't believe as it's getting worse.
They'll do a center diff fluid change for me for $420.
Trans around $1100.

Finding an Indy that's not as expensive is hard in PA.

If it keeps getting worse, I may keep it another year and ditch it instead of dumping money into it.
2016 A6 3.0T 74xxx miles



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Mine is doing the same thing and I brought mine in as it's under aftermarket warranty but Audi quoted the TSB you're going to get hit with saying it's normal because of the difference in speed between the wheels at low speed which I get to some degree (I mean I'm going off an old 4x4 in AWD mode here knowledge wise which I remember making similar noises in 4LO, these are beyond me).

I'm trying to find an independent to do mine as well.

[Audisthesia]

Mine is doing the same thing and I brought mine in as it's under aftermarket warranty but Audi quoted the TSB you're going to get hit with saying it's normal because of the difference in speed between the wheels at low speed which I get to some degree (I mean I'm going off an old 4x4 in AWD mode here knowledge wise which I remember making similar noises in 4LO, these are beyond me).

I'm trying to find an independent to do mine as well.


New 4WD do it as well. Extreme steering angle and very low speed does it. It’s just the difference in tire rotations on each side @ extremes. My 2018 S6 does it as does my 2020 truck. I’m not worried about a thing. The car I have to be completely turned left or right to get it from a dead stop, otherwise it’s non-existent. Perhaps you guys have a different symptom, I dunno.

[Akakios]

New 4WD do it as well. Extreme steering angle and very low speed does it. It’s just the difference in tire rotations on each side @ extremes. My 2018 S6 does it as does my 2020 truck. I’m not worried about a thing. The car I have to be completely turned left or right to get it from a dead stop, otherwise it’s non-existent. Perhaps you guys have a different symptom, I dunno.

Nope, same thing, full lock at low-speed results in Quattro grumble so it is what I thought it was. It is my first Quattro/Sport Diff car. I grew up running RX7s, SC300's and Camaros so my experience is in drag racing.

I have 70k miles now, I just want to get the fluid changed at this point to be on the safe side with sending more power down the line.

[Spitfire007]

Well this is what I can say.
I bought this car with 37k miles on it and it was SILENT and SMOOTH. Not a hint of grumble.
Then suddenly it started, ever so slight and gentle, after I picked it up from a 45k service.
And it's progressively gotten worse, to the point where is can easily reproduce it and make it seem quite harsh and bad.
The fact that it's changing is what bothers me.

I contacted another indy that suggested opening things up and measuring driveline lash (or whatever it's called). He said it would be 5-600 to do both front (or center? Don't recall) and rear diffs and that would at least tell us where to go from there. (I.e: New center diff? Maybe New trans? Maybe something else?)
He HAS had some noises go away from a simple fluid change, but can't guarantee it'll improve. He seems most reasonable.


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[JWebb_C7_Comp]

Well this is what I can say.
I bought this car with 37k miles on it and it was SILENT and SMOOTH. Not a hint of grumble.
Then suddenly it started, ever so slight and gentle, after I picked it up from a 45k service.
And it's progressively gotten worse, to the point where is can easily reproduce it and make it seem quite harsh and bad.
The fact that it's changing is what bothers me.

I contacted another indy that suggested opening things up and measuring driveline lash (or whatever it's called). He said it would be 5-600 to do both front (or center? Don't recall) and rear diffs and that would at least tell us where to go from there. (I.e: New center diff? Maybe New trans? Maybe something else?)
He HAS had some noises go away from a simple fluid change, but can't guarantee it'll improve. He seems most reasonable.


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For what its worth, I had the center differential (Transfer Case) oil change on both my wife's 2017 Q7 (APR Stage 1) and my A6 (APR stage 2), as both those vehicles are a PITA to get centered and level on four stands. The "Audi rumble" has diminished substantially on each. The cost on Q7 was roughly $150 and on A6 was roughly $175.

I don't advocate anything; I'm just providing my experience.

Also, please note that I'm fundamentally frugal and have done maintenance in hopes to run each car 10 years and over 100K miles each.. I've sold my last few cars well over 100K miles and my wife is typically willing to keep hers nearly as long.

[zyrofillica]

For what its worth, I had the center differential (Transfer Case) oil change on both my wife's 2017 Q7 (APR Stage 1) and my A6 (APR stage 2), as both those vehicles are a PITA to get centered and level on four stands. The "Audi rumble" has diminished substantially on each. The cost on Q7 was roughly $150 and on A6 was roughly $175.

I don't advocate anything; I'm just providing my experience.

Also, please note that I'm fundamentally frugal and have done maintenance in hopes to run each car 10 years and over 100K miles each.. I've sold my last few cars well over 100K miles and my wife is typically willing to keep hers nearly as long.

both the Q7 and A6 are on the ZF transmission? im not even sure if mine (non USA model) with the DL501 DSG has a transfer case or seperate fluids to change.

[Botbasher]

both the Q7 and A6 are on the ZF transmission? im not even sure if mine (non USA model) with the DL501 DSG has a transfer case or seperate fluids to change.

It does...both... but getting any info on it seems to be like asking about the Holy Grail!

The DL501 has separate fluids (confirmed by Tech Training Manual and FCP) as does anything with a Sport Diff (ATF & Gear Oil). All of which are claimed to be lifetime fluids (except DSG) by Audi, but we all know what that is worth!

I recently obtained a spare DL501 trans that I am going to try and document the extra fluid areas and how to service them since no one seems to know!

Here is an awesome write up on the operation of the trans and where I found the initial info of the multiple fluids in the DL501!! About 1/2 through Post #1! What they are referring to as "ATF Fluid" is really DSG Fluid, fyi.

https://www.audizine.com/forum/showthread.php/356141-Details-about-the-Seven-speed-dual-clutch-gearbox-0B5-S-tronic-%28DL501%29

Cheers,

KS

[zyrofillica]

It does...both... but getting any info on it seems to be like asking about the Holy Grail!

The DL501 has separate fluids (confirmed by Tech Training Manual and FCP) as does anything with a Sport Diff (ATF & Gear Oil). All of which are claimed to be lifetime fluids (except DSG) by Audi, but we all know what that is worth!

I recently obtained a spare DL501 trans that I am going to try and document the extra fluid areas and how to service them since no one seems to know!

Here is an awesome write up on the operation of the trans and where I found the initial info of the multiple fluids in the DL501!! About 1/2 through Post #1! What they are referring to as "ATF Fluid" is really DSG Fluid, fyi.

https://www.audizine.com/forum/showthread.php/356141-Details-about-the-Seven-speed-dual-clutch-gearbox-0B5-S-tronic-%28DL501%29

Cheers,

KS

Thank you. this information has been tough to find. I have done all my fluids except the DL501. Was thinking of servicing it next finding the elusive transfer case (if any) and hopefully reducing the quattro grumble which has started to appear now at 70K miles.

[Botbasher]

Thank you. this information has been tough to find. ...

I know, and I do not understand why! They are not special fluids. They are easily accessible. They prolong the life of the component.

Why in the hell is it so hard to find info about it. It's like no one knows!! FCP tech, who didn't know, was surprised I knew and even more so when I sent him the manual stating the multiple fluids! He confirmed the fluids but had no idea how much and where to access the Gear Oil side of the DL501 and the ATF side of the Sport Diff. I was a bit disappointed!

Life's a journey and man, am I on a quest!!!

Cheers!

KS

[Spitfire007]

Would love to see the info regarding the the ZF-8 and Torsen Quattro system that is in the A6


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[AudiInMyA7]

Reviving this because I’m having issues, along with an incident with lovely PA roads

What results did you get?


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[Spitfire007]

None. It buzzes and vibrates on tight low speed turns. Hasn't changed, but hasn't gotten worse.


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[Spitfire007]

None. It buzzes and vibrates on tight low speed turns. Hasn't changed, but hasn't gotten worse.

I've had every single fluid changed with no changes whatsoever. Tranny, front center and rear diffs..

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