RS5 Clunky Transmission issues

A5/S5/RS5
#1

Hi all,

I’ve been experiencing some noticeable clunkiness with my transmission. No CEL, no transmission malfunctions, just the rough shifts particularly from 1-2 and 2-1 and some other symptoms. Coming to a stop I’m experiencing the “hump” that feels like you just got rear ended. Other notable issues are sometimes instead of experiencing the “hump” the car seems like it gets stuck trying to downshift from 2-1 and the RPM will bounce back and forth from roughly 650 to 900 until you feather the brake slightly to let the car roll. There’s also a very noticeable metallic like vibration when the car is in R or D, but goes away in N or D. The sound seems to trigger when coming to a stop and the car tries to shift from 2 to 1. And lastly, when I try to reverse the transmission will slip and jerk once or twice before fully engaging reverse and backs up smoothly.

From what I’ve researched, it seems like this is most likely mechatronics unit related. It sounds like initially the whole unit had to be replaced (~$2200), but theres now a revised circuit foil repair for about $450 (Thanks Ape).

I’m making an appointment to have it checked out and will post what they discover but until then, can any of the more technical members weigh in on this?

Appreciate the input as always!

Aleck

#2

What year?

I know the coming to a stop and feeling a “rear end” issue was fixed via a software update from Audi. Have you had any software updates done?

#3

I haven’t had any updates done yet. I came across a few posts that said the software update and/or the re-adaptation process fixed the issue. Do you have any additional info about the software update?

#4

You’ll have to go to the dealer to update the software. Can also be caused by improper fluid level on the ATF side or even a mechatronic going bad as you already know. Start with the simple stuff first though.

If you purchase a Ross-Tech VCDS, you can run clutch adaptation yourself but if it’s at the dealer and money isn’t a huge issue, I’d have them do it.

The metallic ringing is likely a heat shield or hose coming in contact with a portion of the transmission or body. Probably unrelated other than the jerking is shifting components around and causing the vibration.

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#5

Should the software update be done even after going JHM Stage 2(ECU+TCU)?

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#6

If you’re planning on going stage 2, then no, the software uses the latest file as a “base” if that makes sense. But do make sure the car is healthy prior to installing stage 2.

Oh and welcome to the community PCE! Glad to have you here.

#7

Thanks Ape!

#8

Thanks Ape. Initially I figured it was ATF/MTF related so I serviced both fluids (thanks to your video) but the problem continued. I will schedule to have the software updated and look into a VCDS as it’s next on my list. I will keep the thread updated with my results.

I also noticed today strangely enough that the metallic ringing went away when I turned on the A/C. Turned it off and on a few times and it almost certainly seemed to be the issue. Any ideas?

#9

Most likely it’s just a change in the idle speed and the idle smoothing out a bit and not causing the offending parts to vibrate against one and other.

#10

I can confirm the JHM TCU tune solved the clunkiness and harsh 1-2 2-1 shifts for me

#11

The tune does make the transmission shift more smoothly. If I’m not mistaken, it’s built off the latest firmware too which is a bonus.

#12

I had that clunk issue too and I took it to Audi and they ran a software update on mine and it fixed the problem

#13

Today I attempted to get the software update at Audi but the tech said they aren’t sure the TCU is grabbing the update. The tech asked me to drive around and see if there’s any noticeable difference before taking next steps. I will keep updating the thread as I get more info.

Any ideas?

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#14

Sometimes, if the battery voltage isn’t above a certain range, it won’t take the new coding. I would hope they have it hooked up to a battery charger but one never knows.

I know of one other owner where it took the dealer 45 minutes just to get in and code a new battery.

You’re still running the OEM software for the ECU and TCU correct?

#15

Yes - OEM for both. It seems like it’s not a common thing for the software update to not take so I’m thinking it might just be improper procedure. I’m going to call another dealership and see what they think.

#16

Hi all,

Just following up here. Had my Audi dealership do further diagnosis on the transmission shifting issues and I just heard back that the gear oil is mixing internally which caused damage to the mechatronics unit and likely further internal damage. The tech mentioned I will need a new transmission.

I wanted to gather others thoughts on if a brand new transmission makes sense here, or if it’s really the mech unit that needs replaced. I will report back once I have a deeper discussion with the tech.

Thanks all!

#17

After talking to the tech, he mentioned that there was a seal broken on the mech unit. He noted that this could possibly be leading to the fluid covering other components and sensors which is why they are suggesting a new transmission.

Any feedback is appreciated as the new transmission is roughly 15K.

Thanks!

#18

I’m not sure I really understand what they mean about the fluid “mixing internally”, and I wonder if you have a clear idea about that too! I don’t think you mean that the MTF is mixing with the ATF, do you??? That would be rather serious, but if perhaps still the Mechatronic unit has issues with fluid leaking through/around the solenoids, it may just need another Mechatronic unit. I know, still some serious cost! Sounds like you need a 3rd party review/opinion before spending huge dollars…

#19

To clarify, they pulled some of the ATF and MTF fluids and they appeared to be mixing. The tech said it could be one of two things: a seal that’s broken or the MTF side was overfilled with fluid. Additionally, they mentioned that this could potentially be causing issues elsewhere in the transmission but I couldn’t get a clear explanation around other components it could be impacting besides sensors throughout the transmission that the fluids are covering. This is why they are recommending replacing the entire transmission.

The car shifts great outside of the lurch or “rear-ending” feeling when coming to a stop and the same “lurch” when accelerating from a light at a dead stop. Seems to me like the typical mech unit issue and not the entire transmission, but I don’t know enough about the technicals of these transmissions to really say.

I will try to keep the post updated as I call around and do some more digging and start making some decisions.

#20

I think I’d get a second opinion, how many miles on the transmission? Not sure where you live but I replaced a 99k (miles) transmission in my RS5 ('13) with a 25k miles transmission ('15) for 1/10th of that new price. I installed it myself (w/JHM lightweight flywheel) and of course did a full service on it. A different transmission also requires dealer coding (about 30min or less).