Started noticing this a few days ago, a little "pop/clunk" on decel maybe once or twice coming to a stop.

Took the car out today and on the way home it increased by about a thousand times.

Whenever the car is slowing down or at a constant speed (very light throttle) I can hear helicopter popping/clunking or train track sounds from the back half of the car.

Won't do it on acceleration, doesn't increase with RPMs (holding it in lower gear, A4) only increases with the speed of the car.

I'm thinking driveshaft U-joints maybe?
Just replaced front shocks/springs, LCA and relocation brackets, along with an adjustable panhard bar, will check those later.

Its raining out and I can't get the car inside to check so I'm just brainstorming.
Ideas?

 

I have an idea; your car is 1/2 Camaro 1/4 Helicopter 1/4 train track?

 

So whats it worth if I sell it? lol

 

My car does the same thing. Except in my case its my catback. Does your car squeak at idle sometimes?

 

Its definitely not exhaust related, I can feel the clunk.

Just got home from a trip and going to get the car in the air tomorrow, I'm guessing its play in the U joints or something.

It sounds like metal clunking together.

 

Got the car in the air, all my rear suspension components seem to be tight, the only thing that has play in it is the driveshaft.

When I turn it, it takes a bit to actually "catch" and start to turn, and when it does, I can hear/feel a little clunk.

Also it makes an odd noise when I'm turning it "forward" like a low squeak/whine...my car does whine from the rear end at 50+ so maybe that has something to do with it.

Sound like U joints to anyone else?

 

Everything is tight that I installed a couple weeks back (LCA's and relocation brackets, adjustable panhard bar, shocks, and torque arm)

I'm wondering if it has anything to do with the rear end of the car, maybe not just the driveshaft. Driveshaft has play in it as a whole, I tried holding it at the u joint and twisting on either side and there's not much play, not like the whole thing does anyway.

Rear end whines a lot, would definitely like to change the gear oil and inspect the gears, wheel bearings are probably bad as well.

Another thing I'm wondering about is my pinion angle.
With my LCA's and relocation brackets I'm currently set at the bottom most hole on the brackets, could this cause an issue?

 

I would pop the diff cover and look for metal shavings on the magnet. Measure the amount of fluid that comes out as well. I hope it's not the rack/pinion blowing up, but your symptoms seem to point to that.

 

U joints fixed the clunking.

Still going to dive into the rear end and service everything in there that I can.

 

I had chewed up axles and blown up wheel bearings when mine made the helicopter noise. It got to the point of unbearable over 45mph

 

would you say your noise is kinda like if the exhaust were droning in a rythmic way almost but kinda contacted the floor and transferred that? I just got my car back on the road with a tq arm relo cross member new ds etc.. but i know my rear pass wheel bearing is either blown or the axle seal is gone but it definitely didn't sound this bad before? It sounds like you're describing the exact same thing though.