I am going through a suspension overhaul because since I bought the car I cannot figure out where the metallic banging/clunking noise is coming from. Whenever I go through bumps, small or large, the car clunks. It is not a full clunk, but kinda like a metallic bang with a slight clunk. Interestingly whenever I go through a bump with depressed brakes, the noise does not occur ever. Control arms look good, tie rod ends are good, end links were replaced last year, there is no play in the brake pads, sway bar bushings are new. Shocks and struts look fine, but I will change them to be safe since the car is old. I just don't know what else it could be and it is driving me crazy. I've taken it to two mechanics and a dealer, and they don't have an answer.

Yesterday I found that my CV joint has play, and if I move it, it causes a somewhat similar noise to the one I am hearing. But everyone says bad CV joints just crack when turning and my turns are fine with no noise?? I took a video of the noise. Can anyone chime in? Would this explain why I don't hear it while braking? The the rear CV axles have no play. 2008 G35x

 

I've seen and had cars with more play in the CV axle than that. Try pushing or wiggling the outdrives at the diff housing, that will tell you if the diff bearings are going bad. Check your wheel bearings too.
Can you diagnose if the clunk is coming from the front or rear of the car?
One area that I fought for weeks was a clunk coming from the rear hubs. Started after I redid my rear pads/rotors. Turned out that I neglected to properly adjust the e-brake shoes & cable tension, so the small 'toggle lever' (as Nissan/Infiniti refer to it) would rattle/clunk when going over small bumps. Its very fine adjustment, had to have my buddy adjust the cable while I watched the toggles slowly tension with the cable.
Side note, I've had terrible luck with aftermarket sway bar links. I had a set of AC Delcos wear out in less than a few months, boots were fine, but the damn things had a few mm of play in them. I switched to OEM, not problems since.

 

Have you checked your compression rod bushings? They're known to be a source of clunking.

 

CV axles are supposed to be able to move that direction, as the suspension travels up/down the axle needs to expand/contract.

HOWEVER, that would explain your noise, rapid motion on the suspension could be causing it to bang up against something. There is typically enough grease inside that rubber accordion section to keep it from making any noise but then I noticed this part of the video, that looks like a torn CV boot to me, is it? If it's torn then the grease is probably gone and not cushioning the joint anymore.

 

I haven't completely taken it out to check because it looks like a pain but both control arms look brand new, so I haven't bothered checking them. I will check them when I install the struts, however, since I may have to open up some space in the area. Thanks for the reply though.

 

Andrew, thanks a lot for the reply here. I looked again today and the noise is definitely coming from the front. I checked all four wheels. I think from both sides but I may be wrong, although, my right tire is eaten up much more than the left one...down to the metal threads. See the videos to my reply to Cleric670. Does this clunking noise sound like end links to you? I just changed them out last year with Moog ones. I had that noise even before I changed the end links, however. I can't figure it out. I tried checking the end links, but I didn't have enough clearance to put a breaker bar under there...will try again when I do the struts.

 

Cleric670, thanks so much for chiming in. I was really hoping you would get on this thread.

I am with you on the lateral movement. I did so much reading about it yesterday and a lot of people say it is normal to accommodate the suspension. I checked the boots, and they all are in very good condition. However, I do have up and down movement only on the passenger side. Driver side is solid. I have taken videos to help out a bit. Is this movement normal? Will this be causing the noise? Might be helpful to know that I found my right tire to be eaten up on the inside down to the threads. I do not have any vibrations while driving (other than a little from breaking from highway speeds which I think is normal) but I do hear grinding noises (see below).


Here is the noise that I am hearing. When I go backwards, there is the grinding noise. I always thought it may have been just the breakpads touching the rotor but today the noise became much more applified so I am not sure if this is a wheel bearing case. When I go forward, I hear the clunking that I complained about.


Driver side grinding:
Passenger side is less pronounced but not sure if same problem:
Ideas for the causes of grinding and the clunking? Will the lateral CV movement still explain the clunking? Thank you!!

 

Did you ever figure out more about this? I have identical movement on my passenger side cv shaft, along with the clunking noise when I hit bumps. I also get the grinding noise occasionally, but only when making tight turns. Something tells me it has to do with the dust shield behind the rotors.

 

Yes I did. For me it was a combination of bad struts and old calipers. I ended up changing both and coincidentally the noise went away. It was driving me crazy as everything on the car looked fine. The movement on CV joint is normal apparently. If it's grinding maybe worth a check.

 

I've read about the calipers somehow causing a clunk (my guess is something with the guide pins). Bad struts makes sense. Currently have new struts to install, just waiting on a pair of 370Z front coils to swap on.

 

New struts are in with the 370Z springs and the clunk is even worse on both sides (started on the drivers side a couple weeks ago) . Swapping them in required a fair amount of suspension movement and I didn't notice any significant amount of play, or any apparent wear of the control arm bushings. I did notice that I had a small amount of diff fluid leaking out from the front diff (splash shield prevented me seeing where exactly where from), so I'm suspecting the CV's are going out and damaged the seal(s).

 

Just watched all those videos, it definitely looks like excessive play on that front CV axle, hopefully someone else with AWD will chime in a verify this. I haven't worked on the AWD G35 but if it was any other vehicle I'd be tearing it apart to find out why there's so much play.

As for the noise when backing up/driving forward. It sounds like it's coming from the brake rotor, a bad wheel bearing can put a lot of excess stress on the caliper/rotor so also check for ANY play on the wheel bearings. My preferred method is to jack up and support the front, then grab the TOP of the wheel with both hands and violently shake back and forth (basically like a pull/push motion) and if there is ANY PLAY WHATSOEVER then the wheel bearing (or something in the suspension) is shot.

You definitely need to check the fluid level in the front diff, especially if it appears to be leaking. That noise might just be coming from the diff due to lack of fluid. With as much play on the CV axle as you have it wouldn't surprise me if the drive axle seal is blown out.

 

Based on where it appeared to be coming from, I think that it's a very slow leak, possibly from the drain plug, that collected in the crossmember and spilled out. I always look for indications of leaks when I back out of parking spaces (oil cooler seal had a slow leak when I bought it and I've been paranoid ever since) and I have never seen any indications of leakage before today, and I lifted her up more than usual to make sure I could get to everything easier. I'll drop the splash shield tomorrow and look for the source of the leak, as well as check the fluid level and top off as needed.

 

Crawled under her this morning, leak appears to be coming from the left outer seal. Still not seeing any evidence being left on the driveway, and the amount on the upper oil pan below the shaft was pretty minimal, so it appears to be pretty slow. Popped out the fill plug and the level is right where it should be. I also shook the tires pretty good, no play in any direction other than bumping the steering against the column lock. Ordering new CV's and left and right seals today.

 

I recently picked up a new seal puller, Lisle 56750, I think I'm in love, can't believe I went so many years without an actual seal puller (used to use a screwdriver or prybar or drive a screw into the seal then use a hammer to pull it). This would probably be great for the CV axle seals.

For other seals that have a shaft in them (like most rear main seals or cam seals, etc) the Lisle 58430 has been my go-to for a while.