Vehicle is a 2015 GS with luxury package (adjustable sport suspension).

So I've narrowed down the noise to the right rear. It is most noticeable at slow speeds when going over slight imperfections in the road or when going over the curb on my driveway. The sound only happens when the right rear tire moves either up or down.

I checked suspension components during the last tire rotation but nothing was obvious. But that doesn't mean it could be from there as I didn't have alot of time to spend on it.

I'm currently placing a microphone in various locations and listening to the audio to see where it is louder. So far I've noticed a clicking noise when the mic was placed near the top of the shock from inside the trunk. There was no noise at the bottom of the shock, or the lower control arm. I still need to microphone test the caliper, upper arm, and sway bar end links.

Any other suggestions or ideas?

This noise is finally getting to me and it needs to be found! I took it to the dealer and they said it couldn't be replicated....whatever. I recently replaced the sunroof seal so most likely it's not the sunroof or related parts since it only happens when the right rear suspension moves.

 

It could be the bolts holding the sunroof, some members had the issue were the dealer dropped the headliner and replaced or re-tightened bolts.

 

Are these the 4 socket head cap screws used to hold the glass in place on the rails? These are tight and the sound is the same as before replacement of the rubber seal. I did the replacement myself and rechecked my work.

 

No these, the bolts that hold the sunroof assembly to the roof, the only way to get to them is to drop the headliner, but I'm not sure if thats your issuie.

Read through this thread:
https://www.clublexus.com/forums/gs-...in-rear-2.html

 

Is there a way I can test these without removing the headliner? Maybe push against the headliner while driving to reduce/eliminate rail support movement?

 

The only test I know is for the seal. You press the back part of the sunroof glass near the corners and it makes the noise.

 

It's definitely not the seal. The glass doesn't move at all.

Is it possible the shock has failed without leaking? Can the internals get loose to where it rattles?

 

If it was the shock it would leak first, should see some residue if it leaked on the shock itself.

 

robd88 - The noise could be coming from worn or deformed/compressed suspension bushings (struts/shocks, sway bar, etc.). It's getting cold in your area, and that is when worn rubber bushings get hard and can make weird noises, especially if the bushing is deformed/compressed. If the noise goes away when driving in the rain, that might be where it's coming from because the wetness provides a little lubrication of sorts. You could take a spray bottle and spray water on the bushings, soaking them as much as possible, but that's likely not easily done without a lift. I'd also see if banging on the shock housing (vertically as well as from the sides laterally 360°) might produce the sound you're hearing. Also, grab your right-rear tire and push-pull it in the direction of the differential to see if that produces anything...

 

So after spending some time checking all components as suggested (thank you all), I still came up with the noise coming from the top of the shock. So just for fun, I removed the AVS motor sitting on the top of the shock and went for a quick drive....the noise is gone. I only had time for a quick ride since I was on my lunch break, and my ride home from work will be a better test.

I hope it's going to be this simple, but I not banking on anything just yet.

With the part out of the car, it does make a rattle noise when moved quickly up and down, simulating the position when going over bumps. The part is connected to a sheet metal bracket which sits on top of the shock. Next is the test ride. To be continued....

 

I suppose a better test would be to swap the 2 rear units, left and right, and then go for a test ride to see if the noise moves from the right side to the left side.

 

I swapped the two units and the noise is still on the right side. Ahhhhh! Well I guess the AVS motors are both good, and I verified they both work through normal/sport+ selection.

In the recording, the left side is very muffled where the right side has a clicking noise. The noise is pretty obvious, but its origin is still unknown.
Back to more inspection/testing.

 

The bottom of the AVS motor housing has a shaft that slides onto the pin inside the shock tube. The motor turns and rotates the pin to adjust between normal and sport+. The noise is definitely coming from the motor from the shaft bouncing up and down.

Is it possible that the shock has failed to where the pin inside the shock shaft tube is getting pushed up during compression and in turn pushing up on the motor shaft and thus rattling the internals of the motor? I did notice a small amount of oil in the bottom of the shock shaft tube and on the pin.

 

I have an appointment with my local dealer this week to get this fixed. I showed the service writer my findings and if it is the shock, it is covered under original factory warranty.

How critical is it to replace shocks in pairs? If the defective passenger rear shock is replaced, should the driver rear shock also be replaced? Car has 31k miles.

 

I would assume you would want both shocks replaced, since one would be more settled in that the other, it might trow off the ride height on both sides of the rear end.