A slight judder since fitting JHM LWFW

A5/S5/RS5
#72

Interesting it’s the tolances in the gears ( gear lash ) that cause this ! You would think then there would be more than just us two that have this problem ?

The only other thing is it’s more as the clutch engages than when its fully engaged as i can crawl along with no throttle and there is no judder or noise what so ever at 1-2 mph ?
It only happens as the car moves forward from a standstill then once it’s crawling it stops completely ?

I wonder if changing the transmission would resolve this in theory and if a later transmission would be any better ?

How can you find out what code your transmission is ie a PXL or ?

#73

Steve, your transmission code should be listed on the sticker in the boot by the battery and also (at least in N. America) affixed to the inside cover of the warranty booklet. Should have the 4 digit engine code (CFSA) followed by the 3 digit code frear Diff code and lastly the 3 digit transmission code. My rear diff is a MKW in my 2013.

#74

Thank you my friend. I never thought of looking in either of them places, nice one :blush::+1:

#75

I figured as soon as I said it you’d be going, “damn, I knew that”. So what code is yours for the tranny & diff?

#76

Can also use VCDS to scan and see the transmission code.

No idea why it’s happening on two cars and not others. I really do think it comes down to production tolerances and gear lash, especially the front open diff.

#77

Been so busy this week but as soon as I get a minute I’ll look and let you know :blush:

#78

Thanks for that info didn’t think about the VCDS either :man_facepalming:

It very strange it’s so few of us have this issue but like you say maybe ours are a bit slack on tolerances !
From what your saying it’s the front open diff that’s causing this so would changing the transmission potentially solve this ?

While I have your attention any news on the PVC blanking kit yet ?

#79

Out of interest would this help as your saying it’s the front open diff ?

Or could I replace just the front open diff in mine to another oem one ?

#80

You’re really in uncharted territory. If you look at Jay’s installation instructions you can see the range of play in the OEM open diffs. It’s quite a bit. Just thinking you’re on the big end of things and he actually requires that you measure the gear lash before sending yours in to be rebuilt. I’d maybe reach out to them as they have more experience than I do with that. Given the fact he needs to know your car’s original lash, it’s probably returned the same.

#81

No news on the PCV yet.

#82

Yeah I didn’t think about that if it’s the same gear lash then odds on it won’t change !

Just thought it might be a solution, an expensive one I know. If it’s not going to change the issue I’m having then unless it’s 100% I don’t think I’ll take that route to be honest.

I know you have been busy with other projects but where are you at with the PCV blanking kit any closer to having it completed or no closer than the last time i asked you ?
Come on son I’m gagging to get this on my car !! :joy::joy:

#83

If I was in your position Steve, I’d be asking myself if the LWFW gives enough performance increase to justify the chattering and living with the annoyance.
I know my answer would involve fitting the OE flex plate if its a daily driver, I simply wouldn’t tolerate that.

#84

I know what your saying James and it might be the case if I can’t get it better than it is now. Everything I’ve done to the transmission and clutches so far has improved the issue each time so there’s hope yet !

I do love the way it’s made the car feel it makes the engine spin up so fast now and things just seem more fluid with the up shifts and down shifts of the transmission so I’m torn at this time, the car also is running ace atm it’s only in traffic the problem becomes annoying.

The actual flex plate is not the problem as far as I’m aware it’s the flywheel. I have got a brand new RS5 flex plate sitting in a box in the garage so if needs be I can put it on !

I’m not giving up yet I’ve got a few people on the case so we will see and if after this I can not live with it I’ll change it back to the oem flywheel … well maybe lol :man_facepalming:

#85

Wow, Steve et al, I missed all of this…thanks for everyone’s efforts, hopefully we can find a solutions in the near future🤞

Incidentally, my rear differential failed a few weeks ago…and was replaced under warranty thank you universe!!! I am not sure what caused the failure…Audi changed the fluids as part of my 75k service that I had done at 60k and when I got the car back my differential warning light came on. I brought it back to them and they realized that there was an air bubble in the line. They replaced the fluids again and a couple of weeks later I started hearing a noise and the rest is history. Not sure if that was the cause or just coincidence?

When I got the car back it seemed as if the juddering significantly decreased. But now that I’ve had it for 10days ish I think the improvement is slight…or maybe not at all, it’s hard to say. The wheel jerking only seems to happen on the front two wheels during the juddering episodes, which seems to support Michel’s research suggesting the front open deferential issue.

I have definitely enjoyed the improvements that the lwfw have added and can “tolerate” the judder, but if I ever wanted to sell the car, prob never, but if I did, it would certainly lessen its value. It is also a little embarrassing when it starts that loud rattling as I am pulling in or out of a parking lot….and annoying when I pull into my home garage…and just frustrating that my car isn’t running optimally and that it happens to be my car that is this anomaly (and Steve’s of course),

I may/may not get the JHM headers with high- flow cats after I pass my emissions test this August and, if so, I am thinking about taking the 15 hour drive to JHM and have them see if they can figure out the judder and noise when they perform the header install. Per Michel’s note and the back and forth with Steve, it may be that these two cars have funky front open differentials? Michel, did you happen to run your theory by Jake? If not, I can shoot him another email as we haven’t heard anything from him recently.

#86

Hey Adam,

Glad you have caught up on things on here there are some interesting possible reasons why we are having this issue. I do think Michel is on to something with the gear slop in the front diff.

What we need to know or workout now is if there is a solution or a way we can maybe trick our cars via the TCU or ECU or even doing something mechanical so we can at least reduce the effects we are experiencing or totally eliminate them if that’s possible !!

Sorry to hear about your diff I am certain that Audi messed your service up causing a starvation of oil and that caused the diff to give up on you. If it was me I’d be asking them to pay for the lot !!

#87

Hey Steve,

Let me know what you think next steps are…another email to jhm with Michel’s thoughts?

As far as Audi shop, fortunately it cost me $250.00 to replace differential and I figured that it might be tough to definitively prove that they are at fault without a big fight and possible exposure to the fact that my car is modified…so I just covered it, choosing the path of least resistance this time😉

Let me know how I can support efforts to remedy judder.

Thanks!

#88

I agree with Steve that it sounds like the dealers fault. Not sure what they meant by an air bubble in the system? But I also agree with you that for $250 I would keep my mouth shut if I could walk away with a new T.V. rear diff for $250.

#89

Yeah, they might have been b.s. ing me on the air bubble statement….maybe they left it bone dry…

#90

Yes I agree 250.00 is nothing for a new diff I probably would of done the same as it could of been a big hassle if they knew it was a modified car, good choice👍

I think another email would be good to JHM as we have not had anything back from them as to what they think the cause is ?

I would maybe hold fire on Michel’s thoughts and let’s see what they come back with first !
It will be interesting to see what there own thoughts are on this issue !!

#91

Ask them about the supercharger while your at it ahha