RS6 Gearbox expert recommendations

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4.2 V8 40v biturbo - 480 bhp (plus)
Captain Cowpat
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Re: RS6 Gearbox expert recommendations

Post by Captain Cowpat » Mon Feb 20, 2023 3:28 pm

All very interesting. Only this morning was looking at Audi forums.com to find someone doing a diy rebuild. It’s more common than I ever thought. Is this brought on by owners frustration in gearbox shops hesitation in wanting to improve the strength of the transmission?? I don’t know. First port of call will be the valve body pressure relief valve. The Transgo replacement will overcome the pressure spikes which are widely experienced after wear in the VB alloy housing. The second issue is to replace the basket of clutch pack ‘A’. Proven to fail with the pressure spikes, it’s poor design has been upgraded the Cascade Transmission in the US. Using a different design to lock the plates down, it’s made to a stronger spec than OEM for $177. I’m going to find plenty of other problems I’m sure as I go through the box. The upgrade kit from Level Ten will get looked at I’m sure. The only issue I’m unsure of is the TC. I’m reluctant to replace the OEM back into the box. Do any of you guys have a recommendation for an upgrade? I’m looking at stall figures compared with torque curves on US TC manufacturers sites at present and its very confusing!!

Mɐʇʇ
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Re: RS6 Gearbox expert recommendations

Post by Mɐʇʇ » Mon Feb 20, 2023 3:45 pm

I recall when I had my gearbox rebuilt, they gave me an option of a new TC vs a rebuilt one that had been uprated.

When browsing US forums for TC - do bear in mind the very different philosophy of US vs European transmissions.
European ones tend to have more gears and lock up the torque converter early vs US ones which have tended to have less gears and leave the torque converter unlocked much longer.

I'm probably not so far off deciding if my RS6 is a "forever car", in which case the next time the motor comes out I could be interested in some gearbox upgrades to improve it's longevity, or whether I decide I've had enough of it and trade it in for a cheap Aventador.
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Captain Cowpat
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Re: RS6 Gearbox expert recommendations

Post by Captain Cowpat » Mon Feb 20, 2023 3:55 pm

Ah that’s brilliant, thank you mate. Yeah, the US have some pretty strange TC transmission setups I noticed. Those three speed 6 Litre things are another world. Where/what did you settle for in the end? As for forever car, I made that decision last summer when I brought back my C5 100 k miles and 20 years later. Hence my attention to the transmission. Engine shortly after… Just under the opinion that Audi haven’t made a decent car since late 2000’s. Had a go in a C8 and the price and the depreciation just ain’t worth it. Paid £8k for my avant last year and I don’t think you can buy better. Definitely a forever car. Particularly with a good transmission!!

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Re: RS6 Gearbox expert recommendations

Post by d-9 » Wed Feb 22, 2023 3:34 pm

Captain Cowpat wrote:
Sun Feb 19, 2023 9:09 pm
Heyup guys, if I could just add this to the thread and also an update on a thread I started back late last year regarding the same. After having the usual transmission issues widely experienced with the 5HP24, I’ve done what most have probably done on here and researched into the causes of why the box fails. Come to a couple of conclusions and decided to get it done by a pro as work is busy etc etc. Tbh I’m gobsmacked by professionals lack of knowledge and understanding with this whole problem. After visiting an expert Audi garage in the North West after a recommendation, I left totally bewildered. The transmission garage they used were happy to just replace like for like with OEM internals which kind of left me thinking how long before I’m back here again..? I’ve managed to source a complete box from a breakers which had 90k on. The parts Sticker on the box saying remanufactured in 2008. I’m fast approaching the idea of tearing the box down myself and replacing the issues with upgraded parts I’ve sourced in the US. I know tractor boxes are different but , hey let’s give it a go. I have absolutely no faith in absolutely anyone I’ve managed to contact let alone the guys who actually got back to me. ZF have enough info online and I’ve a spare box….
Before you drop the box off, drop the sump and inspect the filter and the metal pipe above the valve body that is mentioned in the links above.

I went through a similar process, but with a 3k mile gearbox that was flaring 1st-2nd under medium acceleration. I spoke to a couple of gearbox places in brum, and unit 20, was quoted £3-5.5k to remove the box, rebuild and reinstall, so I decided to try replacing the metal pipe above the valve body. Around £130 of parts and £150 of oil, seemed better than 3-5k on the offchance it fixed it. I dropped the valve body, but annoyingly the metal pipe was fine, then inspected the filter housing, which turned out to be cracked. Since then I've put about 150miles cross country in wales and the flaring/slipping has totally gone.

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Shoppinit
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Re: RS6 Gearbox expert recommendations

Post by Shoppinit » Wed Feb 22, 2023 4:29 pm

Awesome news. You should update your other thread so people can find the solution.
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Re: RS6 Gearbox expert recommendations

Post by Captain Cowpat » Sun Jul 02, 2023 7:37 pm

IMG_7226.png


I’ve attached a photo of the gearbox underside as I’ve got it on the bench. Hopefully it will show up.. just wanted to confirm which pipe is the culprit when you loose pressure to clutch pack A for 1st and 2nd?

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Re: RS6 Gearbox expert recommendations

Post by JamesLawrance » Thu Jul 06, 2023 5:03 pm

Captain Cowpat wrote:
Sun Jul 02, 2023 7:37 pm
IMG_7226.png

I’ve attached a photo of the gearbox underside as I’ve got it on the bench. Hopefully it will show up.. just wanted to confirm which pipe is the culprit when you loose pressure to clutch pack A for 1st and 2nd?
IMG_7226.png
That's the normal pipe that fails. Cracks where it goes into the casing. Also the sumps are very thin on this transmission, and the filters sit very close, so a lot of filters get cracked or explode.

Captain Cowpat
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Re: RS6 Gearbox expert recommendations

Post by Captain Cowpat » Sun Jul 09, 2023 12:11 pm

That’s great James, thanks. Thinking it was that one feeding clutch pack A. Many guys on here know that that particular clutch drum splits with the excessive pressure caused by the worn oil way on the pressure relief valve circuit. Can we conclude that this oil feed pipe splits, caused by the same pressure spikes I wonder?

JamesLawrance
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Re: RS6 Gearbox expert recommendations

Post by JamesLawrance » Tue Jul 11, 2023 12:32 am

Yeah, that pipe is prone for splitting. Pressure leaks off causes the clutch to burn out.

philS2
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Re: RS6 Gearbox expert recommendations

Post by philS2 » Sun Jul 30, 2023 11:40 am

Damn it. I replaced the smallest pipe (top left) for the 1st to 2nd flaring.
It was split at the flange and when replaced, did reduce the flaring by 90%.
Wonder if I should have changed the highlighted pipe too.
My box had uprated TC/problematic seals replaced and new clutch packs in 2019 and none of these fixed my flaring.
Only when Shoppinit reminded me of the small pipe, did my flaring reduce dramatically.

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Mr Footlong
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Re: RS6 Gearbox expert recommendations

Post by Mr Footlong » Mon Aug 28, 2023 10:53 am

So how did this work out for you in the end JayJay?
Current:

"Brutus"- C5 RS6 Avant - MRC stage 2 - Milltek non-res + 100 cell cats - Wagner ICs - PSS9 - H&R ARBs - OZ Superturismo LM - C6 Custom brakes - HD RNS-E - Various other bits - 555PS/832Nm

Gone:
"Taz"- C7 RS6 - MRC stage 2 - Milltek non-res + 100 cell cats, uprated fuel pumps, race plugs, 745PS/1095Nm
12' Cayenne Turbo, B7 RS4, S3, Cupra R, XJR, EVO VII, STI8,5,2&WRX, 106 GTI&XSI, other crap.

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Jayjay101
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Re: RS6 Gearbox expert recommendations

Post by Jayjay101 » Tue Sep 05, 2023 10:26 am

Mr Footlong wrote:So how did this work out for you in the end JayJay?
Guys still working on the clutch packs last time I spoke to him,I did find you can get uprated clutch’s from greddy


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c5 rs6 owner thats been known to cut the wrong wire.............

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