Rear Differential Noise

[bonhamsurf]

So for the past few weeks, I've noticed a noise coming from the rear of the car during starts. Been trying to figure it out, and today I think I found the problem. With the rear up on jacks, the "Clicking" noise comes from what I think is the rear differential.
My car is a 1991 with 5sp manual with some modifications....

SOS Street Strip Clutch (about 4000 miles ago.)
Nsx-R Final Drive 4.23
NSX-R Upgraded differential.

I recorded our testing today and put the short clips together into 1 movie. The exhaust in the background is not from my car, another in the shop. My car was off the whole time.

Is this an acceptable amount of play/noise in my rear diff? Something I should be concerned about?

I'm about to put a lovefab turbo kit on the car.
Here's the movie....

<div><object width="560" height="315"><param name="movie" value="http://www.youtube.com/v/4I7LdChJf38?version=3&hl=en_US"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/4I7LdChJf38?version=3&hl=en_US" type="application/x-shockwave-flash" width="560" height="315" allowscriptaccess="always" allowfullscreen="true"></embed></object></div>

 

[greenberet]

That is the exact same noise I get when my car is on a lift, the transmission is in neutral, and I rotate the rear wheels. I thought it was play in the driveshaft joints and maybe the differential.

My car is at a shop with the engine out and I asked them to check the driveshafts. They said there was no play at all in the joints. So I guess it’s not worn-out driveshaft joints.

Maybe Kaz or LarryB could diagnose the situation from the video and share their wisdom. Good luck in any case and please post up if you find a way to get rid of the play. The solution would most likely apply to both of our NSXs.

 

[goldNSX]

I have the same noise but don't worry at all because it made it always.

 

[greenberet]

My NSX also makes that noise if I leave the car in gear while decelerating once the engine rpm fall too low. Then the engine starts bucking back and forth and the driveline repeatedly makes that exact same metallic clunking noise until I depress the clutch. I don’t remember the car clunking like that when I bought it back in 1994.

While checking the driveshafts, the shop where my car now is found that the bearing between the driveshaft and the half shaft on the right side of the car is bad. I doubt that caused the clunking but I’ll let you know if replacing the bearing cured it.

goldNSX – since your car has been making that noise since the day you owned it, did you ever look into where the play is that allows the noise to occur?

 

[Larry Bastanza]

Totally Normal, drink beer.

What you are hearing is backlash. If you think about the "connection path" you are moving everything that is in between the wheel to the clutch disk. So all trans parts/gears, etc. have an aggrogate backlash, that is what you are hearing. The sound will change slightly(could be hard to hear) depending if you are in nuetral, or have a gear engaged.

Regards,
LarryB

 

[Sportsmind4me]

Thanks for replying to this thread Larry, I have always heard this noise since I bought my car and I became concerned as I watched the video thinking an expensive repair was in my future. I'm sure I speak for the rest when I say you've put my mind at ease. Now, time to drink that beer!:biggrin:

 

[bonhamsurf]

My NSX also makes that noise if I leave the car in gear while decelerating once the engine rpm fall too low. Then the engine starts bucking back and forth and the driveline repeatedly makes that exact same metallic clunking noise until I depress the clutch. I don’t remember the car clunking like that when I bought it back in 1994.

Mine does this as well, but since I've had other older cars that did this, wasn't too concerned.

 

[bonhamsurf]

Totally Normal, drink beer.

What you are hearing is backlash. If you think about the "connection path" you are moving everything that is in between the wheel to the clutch disk. So all trans parts/gears, etc. have an aggrogate backlash, that is what you are hearing. The sound will change slightly(could be hard to hear) depending if you are in nuetral, or have a gear engaged.

Regards,
LarryB

Thanks for the info!!!

 

[goldNSX]

My NSX also makes that noise if I leave the car in gear while decelerating once the engine rpm fall too low. Then the engine starts bucking back and forth and the driveline repeatedly makes that exact same metallic clunking noise until I depress the clutch. I don’t remember the car clunking like that when I bought it back in 1994.

Now, I know what you're talking about. I have that since day one I've owned the car with 35k miles. I got used to it and press the clutch before the rpm goes below 1500 rpm or then the fuel cut gets inactive.

I don't see a problem.