Noise from the back while parking the car (moving slowly)

[goldNSX]

An owner described a noise his NSX is making while parking to me today. I've never heard of someone who had the same.
The noise (loud scrape) is in the back while moving very slowly and turning at the same time like parking (it can't be heard at higher speeds due to other noises and lower steering activity). The noise exists since about three years and get louder.

I didn't heard it but think it could be
- differential
- axle
- bearing (not very likely I think)

The car is 1992/100k stock. Any thoughts?

 

[usafdarkhorse]

Probably a wheel bearing per another thread with a very similar problem.

 

[EdinKali]

It is the rear diff. They have the wrong fluid in there(no friction modifier).

I tried some Motul without the friction modifier and got the same noise. Slow speed tight turns you get a metallic scraping sound. Didn't hear it going straight or higher speeds.

Changed out the diff. fluid for the Honda MTL and the sound instantly went away.

A while back some BMW's(Z3's I think) came with the wrong diff. fluid and the customers complained about the same noise. The fix was to change out the fluid with the correct stuff.

 

[goldNSX]

EdinKali, thanks for the fast response. I think that's it. The owner bought the car new back in 1992 and said that he doesn't recall that the oil has ever been changed. 100k miles and his still OEM oil gets bad. Makes completely sense to me.

Thanks!

 

[EdinKali]

No problemo.

 

[macspeed71107]

i had the that same sound coming from the rear also. i changed the tranny oil same noise, replaced the axle still had the same noise, replaced the half shaft also same noise. then i treplaced the tranny and problem solved. i then open my old tranny found out my diff was bad the whole time. i plan on buying a new diff and selling the tranny because the tranny had short gears and new sincro in it or i may put the tranny back in the car. i loved the short gears, they made big diff.

 

[goldNSX]

found out my diff was bad the whole time.

Doesn't sound good. What was exactly wrong with it? Clutch discs? Planetary? Bearing?