So this just started in the past few days. I've notices when going from a stop to reverse (and once I stop from back ing up and start moving forward) I get a quick clunk/pop from the pax. rear suspension. It almost sounds like what you get when you have a shifting rear sway bar, but I doubt that is the case because of the nature of when it happens. Nothing on the suspension has been touched in a long time...no change to dampening, ride height or sway bar setting. It is not a up/down induced noise...at least I doubt it is. I can not say that I've heard it while driving around, it only happens when I come to a stop, put the car in reverse and start backing up. If I back up again I do not get it, but if put it in 1st and start moving forward, I'll hear it again. I always happens while in the process of engaging the clutch...clearly when a specific torque load is applied to the driveline/rear suspension when it happens. I think it is getting worse too.

Any ideas?
Things I've been told: Axles, driveshaft, "suspension noises", loose axle nuts or bad wheel bearings. While each problem seems plausible, I'd really like someone to chime in with "yes, I have heard that exact noise before...it was XYZ"

Was under the car- not endlinks. Got the rear in the air and turned the wheels- no noticeable problems/looseness/noises. Could not get any noise from the drive shaft with the wheels in the air.


Video- Some noises are the transmission being put into gear and some are a clicking my brakes make when cold...so ignore those. You can hear the noise I'm trying to figure out at : 24, : 34 and : 40 in the video.

Miata mystery suspension noise - YouTube

 

I have actually heard this noise on my car as well but I have no idea where it is coming from. I have an all stock MSM suspension.

 

Can't be too hard. You can eliminate the suspension in a few hours. Remove the rear sway, check the top hat nuts, shaft nut, and lower nut. That'll leave you with the diff, axles, pff, and hubs.

 

My MSM sometimes does that and I always assumed it was the rear pads shifting. I run XP10 without the retaining clips.

 

I vote pads moving.

What exhaust do you have?

Dann

 

I forgot that someone had suggested this as well (guys at R*Speed)....though I'm slightly apprehensive about how it could be when I come to a stop and start going again how that can cause the pads to shift when I have not changed direction....which I have recently noticed as I can also hear it if I shift carefully without using the clutch. But I'll pull the rear wheels off and check anyway.


Dann- https://www.miataturbo.net/media-53/...-sounds-72247/

 

OK, I finally got some "me" time and got to tinkering on the car. I pulled the back wheels off and inspected everything I could. I also left the car in gear so I could turn the wheels without getting noise from the driveshaft. I could not get any noises with the wheels on the car and pulling/moving/shaking things as much as I could. The underlying "tink" upon a specific driveline torque load was still hear on my way to work this morning though.

What I did find, which I found kinda funny, was the sourse of much of the noise I hear when I drive across flat bumps at a slow speed (expansion joints, speed bumps, cracks etc...)- it turns out the hub-centric rings for my wheels had play in them. I noticed this when I took the wheels off and lightly bounced them on the ground. I also found the rear brake shims to be loose, so I bent them a little bit to put tension back on them. The only other thing I found were the two mounting bolts for the PPF on the diff were easy to add a fair bit of torque to...they weren't loose per se, but with one arm pulling on the ratchet, I was able to turn them a good 2-3 times before they were pretty damn tight. I also found the two bolts that hold the rear part of the Beatrush PPF brace a bit on the "not really torqued down" side and tightened them up. I'm sure all of that will help some, but the "click" upon moving forward is still heard.

Oh, quick question- with the rear wheels in the air and the car in gear- if I grab the axles, how much should I be able to feel them move if pushing pulling them toward the diff/hub? I could clearly feel some play back and forth..not a lot, but some. Maybe 1/16"?? I suck at estimating tiny measurements like that lol.

 

The pads are pretty easy to eliminate. Drive around with the ebrake on a bit. If that doesn't do anything, and it sounds like you've checked all the easy stuff, I'd start inspecting the axles, diff bearings, and wheel bearings. Try not to have a hub failure, m'kay?

 

Yeah, I saw FM's FB post on that. I did give the hubs an ocular pat down when I was poking around under there- looking for cracks or anything unusual, but I did not see anything that jumped out at me.

I'm starting to suspect wheel bearings or axles at this point...only because it sounds like the noise is more outboard than inboard. Given I am about to do the diff. bushings, it'd be nice to swap some axles in, but I really don't have the money for that right now :( (unless I can find some good, used low-mile ones locally)

 

I have a similar noise with my NB, except I get it every time I accelerate hard from a stop. I've been hunting for it for a while and I'm thinking now it has to do with the control arms forward/back movement as the wheel pulls it. I've noticed when doing suspension that it's a very tight fit where my rear upper control arm goes over the knuckle (I have to pull the control arm pretty hard to the side to slide it over the knuckle, same on both sides), and don't know if that's normal, but I get the feeling something is binding there causing the noise.

I'm going to do bushings soon anyway so hopefully that fixes it, but maybe it's something to look at for you as well?

 

Axles should have some axial (get it?) play in them They have to be able to move freely in the tripod cups as the suspension strokes and their length changes. They should have no perceptible radial or angular movement.

Could be any of the bushings. I'd start with the diff bushings and work out from there. Dead bushings usually look it, like all flaky and cracked and terrible.

Could also be bearings, but bearings usually whir and whine long before the clunk. By the time they get to clunk sounds, you've been ignoring them for a LONG time.

 

That's what I'm getting. I might try a drive shaft while I'm at it since it seems that they are a pretty common issue once boosted as well...and for $95 it's worth a shot.

Miiiike- if you remember to, post an update in here when you do your bushings if I have not already posted a solution by then
So hopefully in the next week I'll do the diff. bushings and drive shaft...and then I'll go from there.

 

I now have a click/clunk noise in the back of my MSM under certain conditions. Most i can tell at the moment is when downshifting and not bringing revs up high enough to match. If the rest of the RPMs is taken out somewhat abruptly by the clutch, i get a "clunk" in the diff area.

Le sigh.

 

I'm guessing diff bushings. I've had something like that for a bit and is why I suspect the bushings are toast. If I don't match the revvs well enough (like trying to roll-start the car) I get a decent "CLUNK" from back there :(

This makes me wonder- if the diff. bushings are shot and allowing that much movement, what other parts can suffer from the movement? Hubs? axles? Shaft? ...and how much each part can be affected and what will wear and how they will eventually fail.

 

Not diff bushings in my case. I was the one that initially recommended you do them on your car, since i had just done them on my car. :(

I'm HOPING it's just something loose back there, or some shitty burnt Redline fluid unhappy at being raped on the dyno for 2 hours on Saturday. This noise was not present pre-dyno.

 

Ahhh. I see. I wonder about the drive shaft...or even maybe the exhaust torquing over and touching? 2 hours on the dyno with a lack of good airflow could have done a number on the exhaust hangers back there? (dunno if you have upgraded hangers or not).


I'm still contemplating trying the AWR engine mounts...I'm sure if I do not like them, I could easily drop them in the FS section lol.

 

Try 'em, and if you don't like them, sell them at the end of the season and i'll pick them up. I find the MazdaComp mounts too soft.

I don't have upgraded hangers, but that's certainly an idea.

 

The only thing I would worry about hurting with bad diff bushings is motor mounts.