I've developed a clunking sound in my right front suspension, nothing that changes with speed. My initial thought was a bushing, possibly on the upper control arm. So I jacked up the front end and started shaking/twisting everything; up, down, left, right....no noise or unusual amount of play. So I've started listening to it and comparing to what the suspension should be doing based on the cars motion. Acceleration, deceleration, cruising, all will experience the clunk sound. However, while performing any significant turning, in either direction, no clunking, even on rougher roads. All I can come up with is a sway bar bushing or link (pretty much the only thing I didn't shake when I had it jacked up). Any other things you all can think of?
edit: when I jacked it up i looked at everything and there was nothing obvious. Ball joints all look fine.

 

With the vehicle on the ground pop the hood so you can reach in and have something to hold that won't scratch paint, rock the car side to side and see if that causes the noise.

 

When I got home yesterday I rocked it back and forth while inside, no clunking. Just rocked it as you described, no clunk.

 

Both my G35's needed sway bar end links when I purchased them. When going over speed bumps straight, no noise. When going at an angle, they would 'click' as the suspension works.
It could also be tie rods, ball joints, control arms, etc. Lower control arms are a common failure on v35 cars, not sure on v36 chassis.
Best way to diagnose would be to get the car up in the air (ramps, jack stands, etc) and have a look. Use a prybar to check for play.

 

Sounds like it could be the strut also. They are notorious for clunking when they are going out

 

You didn't say if it's an AWD. If so, check the CV joint.

 

Check inboard on the lowers where they attach to the cradle. The rubber bushing inside the control arm can blow completely out leaving the arm able to move in and out and front to rear dependent on the load being placed on it. It's "captured" by the brackets on the cradle but front to rear you'll get metal to metal contact.

 

Not logical in my mind, but if you can explain, please do, I'm all about learning new stuff on these cars. The noise isn't remotely varying with speed. Low speed, high speed, all sounds the same. Also, doesn't seem like the CV joint would be the culprit based on there being no noise when there is loading on either side of the suspension (right turn or left turn), again, if you can enlighten me so I don't sound like an idiot, please do. I'll be crawling under there this weekend and will report back on my findings.

 

Grasp the shaft between the inner and outer CV joints and try to rotate it back and forth with the wheels strait ahead and then with the wheels turned. Also try pushing the shaft up and down. If the CV joint is worn it will make a clicking sound and there should be any movement of the shaft when pushed up and down. A bad CV joint would cause clicking that will increase with speed or a clunking sound if you shift from reverse to forward or vice versa and accelerate hard. You didn't mention if it is a rapid reoccurring clunking or it is every few seconds or once in a while at random time.

 

Put her up on stands this morning, looks like it's the right front CV shaft. I grabbed it in the middle and twisted, but there was no rotational play. There is noticeable up and down play, with a majority of the play being at the inner end. There's a small amount of in/out play, about what I would expect with the end of the shaft being splined.

 

Almost certain it's the CV's. I now have the noise on both sides. Today I replaced the front coilovers (with 370Z coils, the fender gap looks much better) and rear shocks and the clunking is much worse sounding. Also while I had her up I noticed a small amount of diff fluid leaked out (I smelled it, definitely 80 weight). Looks like in a couple weeks I'll be going under her again. Need to get it fixed before my drive out to Cali next month.

 

Checked for play while I had her up today. Didn't notice anything unusual. Went ahead and replaced the sway bar end links, still a clunking noise.

 

So, I had a thought yesterday while driving home, listening to the loud clunks I now have on both sides. After shaking the crap out of my tires I can generally assume the bushings and ball joints are all good (ball joints all look good on the outside). But then I thought about bushings that would tie into suspension travel, but not really into side to side movement, and came up with this. I'm thinking that my noise might actually be coming from the bushings where the yoke on the coilover attaches to the lower control arm.

It makes sense to me, up/down movement would make it move, turning would cause body roll which would put it under tension in 1 direction (effectively stopping any clunking), changing the coilovers would change the forces being exerted on it.

Anybody have any input to counter/correct my thought process?

 

Lift and support the front end so you can use a pry bar to see how much play you can get on that bushing. Also look for little cracks on the rubber between the inner/outer race, you will definitely need a flashlight on the bushing to help see, I also strongly recommend NOT wiping down the bushing initially, pry/look/pry/look, then wipe it down with a rag and pry/look again. You will need to use your best judgement where to line up the prybar to get pressure on that bushing from various angles.

I'm not a big fan of those factory rubber bushings, one of the best upgrades was the master poly bushing kit from energy suspension. It was pretty time consuming (strongly recommend doing the front first one weekend and the rear some other weekend) though, a 12ton press will be your friend, a couple of the bushings (subframe stuff) I just used a holesaw to hog out the rubber center section then a sawzall to cut the outer race (be careful it's easy to overcut) then a screwdriver to fold the race in on itself.

Be extremely liberal with your poly bushing grease so you don't end up with an accidental squeak. The 8oz tub of their own Energy Suspension grease was enough for the job.

 

I've heard a lot of good things about their stuff, only problem is that they don't have anything specific to the X, and that bushing is definitely specific to the X.