Popping Sound While Turning

[JWreck]

Hi everyone,

I thought I'd share my experience regarding a popping sound I started having in my S4.

Many months ago, I brought my car in for service for a bumping noise when driving over speed bumps. Very noticeable, dealership techs noticed it as well. They replaced something with the sway bar - end links? Seems to have been a known issue.

After that work, whether by coincidence or not, I started noticing a popping noise while backing into parking spots on occasion. I brought it back a couple of times for them to look it over as I couldn't quite figure out how to replicate it. It was happening randomly.

A month or so later, after some spirited driving, I learned that if I apply a hard enough brake, I hear the popping noise. Sounded like maybe the weight shift caused something to flex? It would then ALWAYS do the noise when backing into a spot after hard braking - and I could feel it in the steering wheel.

Now, my car went in and the dealership replaced some subframe bolts that jay not have been torqued to spec. Still had the issue. Car went back in this week for the regional Audi field manager to help diagnose it. At this point, they're thinking it's the diffs. They drove me around and did a great job finding all the ways to replicate it. So they are ordering a transmission.

I'm happy to be making progress, as the popping was very loud and very embarrassing with passengers in the car! Throughout all of this, surprisingly, the dealership has been spectacular. They have kept me updated appropriately, pushed through to find a resolution and I couldn't be happier.

[EHesh14]

Wow that is awesome that they are replacing the tranny! I notice the same popping sound when I turn into a dip. I believe it's the rear sway bar bushings and someone recommended wrapping the bar that attaches to both
Bushings in thread sealant or something similar

[S4'ed]

Could be many things....but I doubt its the transmission !!
Also, since it from forward-to-reverse hard braking, I doubt it has anything to do with the swaybar center bushings or the endlinks. Could be your subframe shifting, but it sounds like the dealer checked that and replaced/tightens the bolts.

The below components take all the lateral forces when braking :
Check all four control arm bushings (4 bushings) and 4 ball-joints. The upper arm inner bushings start to tear as early as 30,000 miles, with this (not so durable) Audi suspension design.
Check tie rod ends, and inner balljoints.
Check brake pads and caliper slide pins, and the pad retaining spring clip.
Check that the bolts that hold the brake reaction bracket to the upright/wheel bearing housing are tight.

[mungie]

I had a loud popping noise when cold and turning over bumps. I retightened my front calipers and haven't heard it since (2k miles). Keep us updated! That's a hell of a service order

[JWreck]

Could be many things....but I doubt its the transmission !!
Also, since it from forward-to-reverse hard braking, I doubt it has anything to do with the swaybar center bushings or the endlinks. Could be your subframe shifting, but it sounds like the dealer checked that and replaced/tightens the bolts.

The below components take all the lateral forces when braking :
Check all four control arm bushings (4 bushings) and 4 ball-joints. The upper arm inner bushings start to tear as early as 30,000 miles, with this (not so durable) Audi suspension design.
Check tie rod ends, and inner balljoints.
Check brake pads and caliper slide pins, and the pad retaining spring clip.
Check that the bolts that hold the brake reaction bracket to the upright/wheel bearing housing are tight.

I'm normally skeptical, and still slightly so, however we're now out of my league and I've been working directly with the shop foreman throughout this and I do feel comfortable with his extensive knowledge. Since we're out of my depth, I'm trusting that whatever they're doing is the right path. I have a hard time believing that the dealership would put a lot of money on the line for the transmission part and time cost for the swap without having checked other things first.

I've been wrong before, but given that they're working directly with the AoA Field Service Manager on this (who approves and denies warranty claims), I'm confident they're not jumping to conclusions for the sake of it.

Obviously time will tell - once they get the transmission and diffs swapped, we'll see.

[JWreck]

I had a loud popping noise when cold and turning over bumps. I retightened my front calipers and haven't heard it since (2k miles). Keep us updated! That's a hell of a service order

Yeah that sounds similar but mine isn't temperature dependent.

They did also determine it's not just forward to reverse, but while turning as well. It was some fairly extensive testing to reproduce it (including something that allows them to listen with headphones via a microphone placed inside of the engine bay or near components?). They reproduced it not only by hard forward and reverse braking, but turning as well.

I can only talk about it so much since a lot of it is more in the weeds than I've been before. I may not be using correct terminology to describe parts.

[jygesq]

DSG? Or 6 sp MT ?

[JWreck]

DSG

[RudyH]

Had the same issue, my shop and even the Audi dealership couldn't figure it out and wanted to throw parts at the problem which the warranty company wasn't happy about

Thought I would ask them to check one item before, on the suggestion of the forum, and it was sub frame bolts.

[JWreck]

Had the same issue, my shop and even the Audi dealership couldn't figure it out and wanted to throw parts at the problem which the warranty company wasn't happy about

Thought I would ask them to check one item before, on the suggestion of the forum, and it was sub frame bolts.

Yep, that's one of the first things they checked. At first they said they may not have been torqued correctly, then after torquing them they wanted to replace them because they may have been stretch past spec.

[RudyH]

Yep, that's one of the first things they checked. At first they said they may not have been torqued correctly, then after torquing them they wanted to replace them because they may have been stretch past spec.

ah sorry missed that in the fifth paragraph, finished my morning coffee now!

[JWreck]

Well, they replaced the transmission and it fixed the issue with the diffs, but the biggest popping noise was still present. For that, they found that a strut wasn't torqued properly. Fixed! They're doing an alignment and then I get her back tomorrow. I'm so excited, it's been two whole weeks in this loaner Q5 2.0 and its S L O W.