A Clunk...Got any guesses?

[Dmb408]

So...

Car was in this past week for DRC and definitely two torn bushings (that I could see) on left FUCA's. Turns out it was smart to do all four FUCA's because there was some play in the ball joints on all and the other bushings were starting to tear too. So anyway, 4 new control arms later and a DRC recharge from 8 to 16 and 10 to 16 on the two diagonals respectively and the car should be tight as a drum right, well it is (on the hwy home)...but...

There was this clunking when I took it in and I thought oh that is DRC clunking (being that this is my second DRC RS6 and I had an RS4 pre DRC recall with bad struts) well with everything fixed I pull out of the dealer and I hear the clunking. Turn around, go back in, and am like WTF. R8/RS master tech comes out from the back and is like lets go for a ride (super cool guy btw). He heard the clunk and was like no that isn't DRC. Can't be sure what that is but your car sounds pretty darn good compared to the other RS6s I work on "very quiet for an RS6" was his quote (an RS6 was on the rack when I dropped mine off last week so they get a lot). He said we'd spend tons of money chasing something to find it. He said drive it for 6 more months maybe it degrades more and he can find it more easily. He said maybe it could be trans cradle but any other guesses from you guys? He also said our car doesn't not electronically sense bad motor mounts through Vagcom, but I thought it did, is he right or wrong on that.

It is a clunk when I go over a slight bump, usually at slow speeds. It is really f***ing annoying because I am so anal about cars but I need to just relax and be like 12 years old, car is in great shape, relax.

[Dmb408]

I think maybe it could be this... http://www.rs6.com/showthread.php/23...h-Bolts-part-s

[Other_Erik]

Trans/diff mounts? Does it sound like coming from the rear of the car? How's your sway bar mounts look?

[Dmb408]

Sway bar mounts are pretty rusty if i recall. I actually haven't got under this car yet, the belly pan is so bad I can see things though. There is no excuse though, I'll put it on the "race ramps" (<--- awesome product) and look this weekend. I hadn't focused on front vs rear isolating yet. But from recollection I'd say right near trans/engine mating area. (so middle of car)

[Other_Erik]

I hadn't focused on front vs rear isolating yet. But from recollection I'd say right near trans/engine mating area. (so middle of car)

If it's at (as far as front/rear) the trans/engine mating area, which is actually further forward than you might think, I'd put money on sway bar mounts/bushings. If it's further back than that, trans mount is suspect #1.

O_E

//Edit - if it's even further back, diff mount could also be a culprit.

[ben916]

It is a clunk when I go over a slight bump, usually at slow speeds.

Coasting or slight throttle?
turning?

Where is the clunk at in the speedbump? Beginning, end, middle, front tires/ rear tires???

If you have a GoPro, you could set it up to record under the car, either under the car or on pavement, the location of the sound and/or the offending item.

She is a finicky BEAST!

[Dmb408]

Your last point is the good one ben and basically the tech's feelings - i.e. we could spend forever chasing this replacing items.

I believe it is coasting and i think is eliminated on turning if my memory serves. I will check the coasting vs throttle thing on my way home tonight.

[lswing]

Still the DRC...I had a clunk once, removed the DRC and all better!

[Bigglezworth]

Is it more pronounced when you are turning one way vs. the other, or changing elevations like you would in a parkade or up a curb? If so, my money is on sway bar end links. When I first put in my Hotchkiss sways, I had a clunk that wasn't there before and with having performed only the one revision prior to said clunk was able to quickly confirm it being the end link.

[ben916]

Is it more pronounced when you are turning one way vs. the other, or changing elevations like you would in a parkade or up a curb? If so, my money is on sway bar end links. When I first put in my Hotchkiss sways, I had a clunk that wasn't there before and with having performed only the one revision prior to said clunk was able to quickly confirm it being the end link.

If that is truly the case, installing Hotchkis Sways is as easy as installing front rotors and pads.

[Dmb408]

Are those end links replaceable without removing the strut? Does car/wheels have to be unloaded/loaded?

Anyway i did some checking this weekend. Those bushings look aged but they have NO visual tears but is definitely from that area, almost right below my driving feet. But what I did notice after analyzing all weekend is there is the clunk but then there is a slight hollow marbles in can type sound that i think is the rear diff mount. So I think I am chasing two rabbit holes.