Axle/CV "one time" knock

[Matt Shover]

The subject is a bit of an assumption...

91 NSX with about 120K on it -- getting a "one-time" knock upon acceleration or stopping (it will knock once per action, NOT a persistent clicking or knocking sound with each rotation). Sounds as if something in the axle or hub is turning just a few degrees that it shouldn't be.

A friend with an S2000 said he had a similar problem that ended up being a bad axle that was replaced under warranty. Since I've been out of warranty for, oh, about 12 years now... ... was wondering if others have experienced this as well.

If it's the axle, is it typically the inner or outer joint? Any ways to test to assure it's the axle?

Thanks for your help!

-Matt

 

[Larry Bastanza]

Hi Matt!

Hope all is well with you. I suggest you have a look at your front/rear motor mounts.

Sorry not to see you at NSXPO.

HTH,
LarryB

 

[CK_SB]

Hi Matt,

Did you ever determine the cause of this noise? I have a very similar symptom and have not found any engine mount issues, loose sub-frame bolts (or any loose bolts for that matter), broken or cracked components, or loose or damaged struts or springs. I am suspecting a bind in the plunging action of the CV joint. I theorize that a bind occurs under load, and when the load is reduced the bind releases and the axle shaft bangs back into the inner CV joint cup, making the single "clunk" sound. This is just a thought/theory on my part as I haven't yet resolved the issue. My car is a track only car and the rear suspension is heavily loaded during cornering, and the rear suspension geometry is operating out of its normal range of motion, so our causes may end up being different, but I am curious to know if our cars are experiencing the same issue. If you have discovered anything please let me know. My pm is [email protected] .

Larry B., Please feel free to chime in here if you have any new ideas.

Thanks,

Chris

 

[53heloFE]

Could be a brake issue too couldn't it? I have had brakes do this that are loose. They move forward upon stopping and hit the assembly making a knock, and when accelerating they move to the back side and knocked then too. Can you tell for sure it is coming from the rear where the CV joints are?

Just trying to throw some other options out there.

 

[Semnos_NSX]

Matt Shover,
If you ever figure out what that noise is, please post it because I am experiencing a similar noise. The first thing that comes to my mind is motor mounts, but I have checked them and they look fine. I will be taking my car to either Autowave or Greenlight within the next few weeks to have some work done, so I will ask them what they think.

 

[CK_SB]

In my case it is not the brakepad shifting type noise. I am very familiar with that noise. This noise is a serious sounding, heavy, single clunk while on the throttle and in the corner. I am wondering if the diff's clutch pack is getting hot and unloading, or the right axle has a problem. The noise appears to come from the right rear and it will do it most frequently in hard left turns. The noise, in my case, occurs only once or twice in a given lap, to give you some idea of the frequency. Thanks for taking the time to throw out a new idea...keep them coming. I'll probably pull the trans. soon and if I find a diff problem I will post my findings for others who may someday have to deal with this weird noise.

Chris

 

[Semnos_NSX]

Just out of curiosity, does the knock sound more like metal hitting metal or more like a thud. I ask because mine sounds more like metal hitting metal in a knock form. Does that make sense?

 

[CK_SB]

Not speaking on behalf of Matt, but my knock sounds like a heavy metalic impact. Imagine a 32oz hammer hitting the center of the CV joint while in an increasing radius, 120-150 degree corner and you can possibly get a sense of this unusual noise. I have been brain strorming this problem with some others and I have a few tests to run that should help to isolate the problem. This is a weird one. I was hoping that some other Prime member had run into this before and would post so that I could save some time. Looks like I'll be investing the time sooner then later.

 

[khappucino]

bad ball joint?

 

[Semnos_NSX]

bad ball joint?

That’s funny you said that. A couple of weeks ago I notice a scraping noise coming from the rear tire and thought it could be my brakes so I checked them out. It turns out my rear brakes were bad, but upon inspecting them I noticed that the rubber boot on the ball joint was torn and the grease was mostly gone. Do you think that sound could be coming from the ball joint? :frown:

 

[Matt Shover]

Larry, All -- thanks for the comments. I'll be looking at the problem this weekend and will get back to the thread on this one. The noise is getting a bit worse now -- more of a "thud" than metal on metal, but that's just my perception.

I had a similar problem in the past with a brake -- tightened the caliper bolts down and it went away. After reading Larry's comments, I do suspect the front/rear mounts. Will update you all as soon as I know.

-Matt

 

[khappucino]

That’s funny you said that. A couple of weeks ago I notice a scraping noise coming from the rear tire and thought it could be my brakes so I checked them out. It turns out my rear brakes were bad, but upon inspecting them I noticed that the rubber boot on the ball joint was torn and the grease was mostly gone. Do you think that sound could be coming from the ball joint? :frown:

well i know that after i got my ball joint regreased and new ball joint boot, my ting... sound went away... although 2 days later i blew a coolant hose... lol but thats a different story =)

 

[Larry Bastanza]

Matt,

First thing I would do is loosen the front and rear motor mount through bolts. From the drivers seat put the car in gear and pump the clutch lightly to get the drive train to "rock" back and forth to seat the mounts, then torque them down. This is assuming fo course during your inspaction you do not find anything obvious. Look carefully at the CV boots too. For the inner joints grab the boot and press. Make sure you do not feel and "object" (a lump) inside the boot. This would be an indication a bearing has moved out of position. This is not likely if the boot is intact, but check to be sure. The other possibility is just gear lash from the dif, although you seem to say less of a metallic sound , which tells me otherwise.

Chris,

Your problem sounds like a shock/suspension problem. In regard to ball joints, etc, these are all possible. You will need to do a complete inspection for play is every joint in the rear suspension. Also check your shocks. First for external leaks, then best way to check for an internal shock failure is to take the car out and work the suspension, then check the outer shock body temp. If one is colder then the others, that's your bad one.

For bearing and tie rods, get the wheels off the ground, the but your hands at 12:00 and 6:00 o'clock and press in/out on the wheel. This will help find a bad ball joint or bearing. Then try 3:00 and 9:00 o'clock to inspect the tie rods(toe links/tie rod ends in rear, tie rods and tie rod ends in front).

BTW, if you track your car you should be checking all of the above often. I have had to replace the hiem joints(Comptech and SoS toe links) and tie rod ends(rear), tie rods and tie rod ends(front) on tracked cars, especially if you are running track tires. A car will not pass tech if ANY loosness is felt in these areas, it's just not safe.

HTH,
LarryB

 

[khappucino]

That’s funny you said that. A couple of weeks ago I notice a scraping noise coming from the rear tire and thought it could be my brakes so I checked them out. It turns out my rear brakes were bad, but upon inspecting them I noticed that the rubber boot on the ball joint was torn and the grease was mostly gone. Do you think that sound could be coming from the ball joint? :frown:

=o if you havent changed the ball joint boot yet, you should, its alot cheaper then buying the whole upper/lower arm + ball joint assembly since you can't just get the ball joint i believe

 

[Semnos_NSX]

=o if you havent changed the ball joint boot yet, you should, its alot cheaper then buying the whole upper/lower arm + ball joint assembly since you can't just get the ball joint i believe

Thanks for the info!! :wink:

 

[Matt Shover]

Larry -- right you'd be! Upon getting under the car, I noticed the bolt that that secures the mount (right by the subframe brace \__/ looking thing) was MISSING. I believe it's part number 90172-SLO-000 ( http://www.nsxsc.com/nsxparts/2-c7.jpg #7 on the right diagram).

Additionally, if you don't mind, would you describe what gear lash from the differential would sound like? I noticed that there is a metallic sort of "clunk" sound when I rock the wheel back and forth -- with the sound coming from where the axle goes into the tranny. Is this normal?

Thanks again! Hope to catch you soon at an NSXPO (really, the west coast NSXPOs are far too easy to actually go to with me actually being ON THE WEST COAST...)

-Matt

 

[DutchBlackNsx]

I had a lot of the clunking as described here.
Took both driveshafts off, dismantled them completely, even took the bearings and needles apart. Cleaned the lot realy well, put it all back together with highpressure grease 'molybcoat' (or something), new boots the lot.
Is much, much, better now.


Mich

 

[Larry Bastanza]

The gear lash is the play between the ring gear and the pinion gear. If you raise the car, just rotate one wheel back and forth. You will feel it. Typically you get this sound as you are featering the throttle on off, backing the car up a slight incline and "milking" the clutch.

If you are moving forward very slow and the engine starts to lug, you will here is too, as the car starts to jerk for/aft.

HTH,
LarryB