Odd cluking and jerking in stop and go traffic. 8-speed 2014

[ericthecmh]

Hey guys,

Before I get started, I know there's probably a dozen possible reason for this. Just looking for some ideas on where to start investigation.

Basically, in stop and go traffic, when I'm coasting between 10-20 MPH, my car will jerk a bit every time i let go of the throttle or when I reapply it. According to the dash, the car in is second gear. I notice the jerk always lines up with the tach dropping/jumping back up when I let go/push down on the throttle. The RPM drop/jump is usually from 2k->1.2k and back. Sometimes, the jerk as also accompanied by a soft thud.

I have a 8-speed 2014 audi a4 with 26k miles. Transmission fluid was changed amount 2 months ago.

Is this normal for my car? If not, what might be the cause? I'm thinking about checking the motor and transmission mounts. Anything else I should look for?

Thanks!

[Grippy]

26k would be a little early for motor/trans mounts, but it's worth a look. 2nd is notoriously jerky with the 8spd- i feel it all the time, and sport mode seems to help by getting the rpms up. Something others have done is add the transmission and differential mount billet inserts from ecs or 034. I'll let some others pitch in before actually recommending that. But the jerking in that gear and those speeds is inherent, and probably more noticeable as the motor and trans mounts wear. I'm at 19k and I'm wanting to try the inserts more and more as I notice slack in the drivetrain.

[Novarider]

Is it shifting from 2nd to 3rd or 2nd to 1st when it does this? You could put it in manual mode and leave it in 2nd to see if it still happens.

[ericthecmh]

26k would be a little early for motor/trans mounts, but it's worth a look. 2nd is notoriously jerky with the 8spd- i feel it all the time, and sport mode seems to help by getting the rpms up. Something others have done is add the transmission and differential mount billet inserts from ecs or 034. I'll let some others pitch in before actually recommending that. But the jerking in that gear and those speeds is inherent, and probably more noticeable as the motor and trans mounts wear. I'm at 19k and I'm wanting to try the inserts more and more as I notice slack in the drivetrain.

Thanks for the input. I got the car CPO but I'm pretty certain all the miles were in traffic, so I figured the mounts would wear quicker.

I'm glad to hear some jerkiness is inherent though. As long as nothing's wrong I'm not bothered much, don't care so much about the actual jerking. Regarding the inserts, I actually had ordered one over the weekend, should be getting here tomorrow :D

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Is it shifting from 2nd to 3rd or 2nd to 1st when it does this? You could put it in manual mode and leave it in 2nd to see if it still happens.

Nope, no shifts. I have put it in M to test that; it's remaining in 2nd. I also did the tweak to show the gear number in D and it remains at 2 the entire time

[Grippy]

Let us know which insert you got and if it helps!

[jn1kk]

Stop and go traffic jerkiness, after much research, seems to be inherit to the ZF8HP and doesn't seem isolated to Audi (BMW owners seem to experience this too). I have the same problem. I'm about at 40k (2015 A4), but the thing you have to watch out for is escalating symptoms. When my car downshifts 3->2, 2->1, it would do it too early and would rev up to 2K RPM and kind of jerk you forward a bit, giving a very unpleasant feeling. I brought it to Audi twice. First time they did a clutch adaptation. Second time, the took oil sample and sent it to Audi along with another clutch adaption. They said to come back in 1000 miles, and they call TAC which will tell them what to do (replace transmission, buy car, maybe even do nothing). But service advisor said something will be done about it. I believe its a TSB. Not sure which one, but I believe its this one: 2030007

http://www.revbase.com/BBBMotor/TSb/...dPdf?id=196460

Just sharing my experience and research.

[Audi 911]

Hi, I own a 2013 Quattro A4, CPO with 25K miles. I also had the jerking and a harsh bump at low speeds. It seemed like the transmission could not make up its mind what gear to be in, then it would abruptly down shift usually under braking. I found a service bulletin # A3716690293 NHTSA number 10094622 it provides software for the transmission control module. The bulletin was issued 9-30-2016. The dealer updated the software (3-4 hours) and only charged me $80 as it is covered by the CPO warranty (otherwise $360 or so). It completely fixed my shifting issues and now the car is smooth shifting in both D and S (rarely had issues in S). Not sure if your jerkiness is caused by this but if you haven't updated your original transmission software I recommend you start there.

Cheers!

[acidvoodoo]

You could try doing a throttle body reset. I experienced the same feeling in my 13' during stop and go traffic, did the reset and it smoothed the shifting out.

https://www.audizine.com/forum/showt...1#post12967650

[ericthecmh]

Thanks for all the suggestions! I will definitely check them out

Let us know which insert you got and if it helps!

Will do! Unfortunately it came the day I left for vacation, but I'm back next week and can't wait to try it.