6HP19A Flange Play

[zit501]

Hey everyone,

I've been searching for the source of a high-speed vibration for over a year now. I've checked and replaced so many things. The only upside of all of this so far is that the list of possible sources is getting shorter...
One of my possible sources is play in the front right diff flange. I found this video on youtube from a guy who seems to have almost identical play, however he sold the car before finding out if this was the cause of his vibration.
I asked some ZF specialists on the net if this sort of play is normal, and got what I think are inconclusive answers. I also visited ZF themselves and had one of their tech's check it out on the lift. He said he thought it wasn't the cause, but he also said he hadn't really worked 6HP's very much... (great from ZF themselves)

So I reach out to you fellow 6HP19A owners! Perhaps you've been under your vehicles and checked this out before? Perhaps you're going to be under your vehicle soon and can check this out whilst under there? Please watch the video and report back if you are able to. It's like the flange can be rocked up and down.

If one looks at the diagram below from SSP 385, it shows that the flange isn't actually located within a bearing, it simply rides inside the diff. So this leads me to believe that this play 'may' be normal.
ssp385.jpg

Whilst I'm searching for any possible cause and solution though, I've got to tick this one off.

Just as a side note, I've so far replaced: front bearings, one hub, all front suspension arms, rack and rod ends, all front CV's (inners and outers), subframe bushes, wheels and tyres (although this is still a possible cause, I'm running spigot rings which I've tried a few sets of), alignment and balancing done many times.
Vibration is from 100km/h upwards, but mostly between 110 and 120.

Many thanks
Mark

[lynalldiscovery]

Not much help I know but I tend to work on land rovers and trucks and without exception all the gearbox output flanges have a degree of play, some have what I would call to much, but they dont make noises and dont leak oil and have been like it for hundreds of thousands of kilometres.

Have you tried a set of std wheels?

[zit501]

Not much help I know but I tend to work on land rovers and trucks and without exception all the gearbox output flanges have a degree of play, some have what I would call to much, but they dont make noises and dont leak oil and have been like it for hundreds of thousands of kilometres.

Have you tried a set of std wheels?

Thanks for the reply. It all helps. I've got another guy on another Audi forum who's doing a front bearing this weekend, so he's going to give his a check.

When I got the car I had standard 17's, which were buckled so I got them straightened. I then upgraded to 18's from a B8 which need spigot rings. Where I lived at the time, I hardly ever went on the highway. I've recently moved to Cape Town and to get to work I have a really nice open highway run every day. This has accentuated the issue, but at least I can now check any possible tweaks each and every day!

I've checked the B8 wheels I have now, they're definitely straight. I also had the tyres road-force balanced (in addition to many other balancing sessions).

My latest theories are either:

• front shocks are dead (I have air suspension so it's tough to change these...)
• Prop-shaft is out of balance or centre bearing dead (I have a new centre bearing and carrier to change out)
• this front-right flange making the front right driveshaft wobble
• Spigot rings are not great. The ones I have on now are plastic, but they fit snug. I bought a set of aluminium ones, but they have about 0.8mm of play on the ID.

the main contenders are the spigots or the prop-shaft.

[54A4Avant]

Do you know what your car’s block 93 readings in engine module of vcds are? I only ask because I had a vibration around 100-110kph which disappeared after replacing bank 2 upper timing chain tensioner. It seems the failing old tensioner introduced a marginal timing imbalance between the two sides of the engine, and this resonated at around those speeds.

My block 93s were around 7-8 deg on Bank 2 before the replacement , and 0 deg after, so I wonder if block 93s above 4 or 5 might be a potential source of a vibration at around the speeds you mentioned.

[zit501]

Do you know what your car’s block 93 readings in engine module of vcds are? I only ask because I had a vibration around 100-110kph which disappeared after replacing bank 2 upper timing chain tensioner. It seems the failing old tensioner introduced a marginal timing imbalance between the two sides of the engine, and this resonated at around those speeds.

My block 93s were around 7-8 deg on Bank 2 before the replacement , and 0 deg after, so I wonder if block 93s above 4 or 5 might be a potential source of a vibration at around the speeds you mentioned.

Hey 54A4,

That's in interesting cause! I don't think that's my issue, since the problem persists when I kick it into neutral. I'm also TDi, as opposed to your FSi. But I have replaced one of my top tensioners before. Thanks for the tip though.

An update on my issue for those who care: I removed my front diff and took it to ZF. They were worried with the amount of play on that front right flange, at first. Then after querying with Germany they were told that it's normal...
I also had the propshaft checked, but think the guys who did it were a bunch of sharks. I'm going to do some more under-car Go Pro recording to watch the prop. I've done it on all 4 wheels and they don't seem to be bouncing at speed.

I'll solve this on day!!

[JUSTDAVE2020]

Hey 54A4,

That's in interesting cause! I don't think that's my issue, since the problem persists when I kick it into neutral. I'm also TDi, as opposed to your FSi. But I have replaced one of my top tensioners before. Thanks for the tip though.

An update on my issue for those who care: I removed my front diff and took it to ZF. They were worried with the amount of play on that front right flange, at first. Then after querying with Germany they were told that it's normal...
I also had the propshaft checked, but think the guys who did it were a bunch of sharks. I'm going to do some more under-car Go Pro recording to watch the prop. I've done it on all 4 wheels and they don't seem to be bouncing at speed.

I'll solve this on day!!

Hey new to this forum and looking for some assistance, I have what sounds like a very similar concern as you have had. Did you get a solution to it in the end?
Like you the play in the gearbox flange was a consideration on possible cause but unsure if normal.
The sweet spot for it to occur seems to be 58-70mph and fades out higher speed but you know it's still there. I get a faint steering wobble at 50mph also(lower arm has slight play and will change this possible cause) then it goes and the big vibration comes in more so through the car. Spoils the full enjoyment off driving it.
Can you run the quattro (a4 b7 3.0 tdi)on a ramp with the propshaft off and the fronts will just turn??

[zit501]

Hey Just Dave,

So since last year I've had a few minor developments on this. I've changed jobs, which has resulted in me having a much shorter commute to work, where I also don't get above 90km/h or so. Therefore I'm not reminded of the issue every day!

However I did try one more intervention which seems to have helped a little, although I can't be too sure due to lockdown resulting in much less driving. I picked up a really cheap deal on two decent front driveshafts in the UK off eBay. I had these shipped to my cousin, then brought them back home in my luggage late last year. To my surprise the right shaft came with the output flange! I cleaned and rebooted both shafts. I first installed the left one, with no change in the wobble between 110 and 120. Then I changed the right one AND the output flange, and although I haven't given it a proper test, I'll say that it's slightly better. Not gone, but better. The output flange still has play with the new flange. Similar levels to the original one. So either there's wear in my diff, or it's normal. I'm leaning towards it being normal since the ID of my diff didn't look polished from the flange, that I remember anyway.

Where else the wobble comes from... I guess it's either rear diff and/or shafts or propshaft. But I'll likely not pursue this any longer. The vehicle is driving really well, and the wobble is nowhere near as bad as it once was. I also don't do much distance highway driving.

To be clear, I had already replaced all 4 CV joints on my front shafts, before replacing the entire shafts this year with second hand OEM shafts off eBay.
In addition to the shafts, I have also replaced:
All front suspension arms
ARB drop links
ARB bushes
Front wheel bearings
One front hub
Front Subframe bushings
Front and rear brakes and pads
Front Right engine mount
Gearbox mounts
Wheels and tyres a few times.
Spigot rings for my wheels a few times.
Had alignment done a few times.

I have air suspension, so it's difficult to replace the shocks, but they have both been refurbished due to blown bellows.

So once again, I have no conclusion for you dear readers.
I am sorry.

[zit501]

Oh, to answer your question, I believe you could indeed run the front on a ramp with the propshaft disconnected. There's no load to trash the torsen diff, and it'll likely lock up enough to transfer "full power" to the front diff.

Let me know if you try this.