Grinding noise from rear driver's side under load

[cyanutopia]

Hey fellow Primers! I have a new-to-me 1998 Acura NSX with 30k miles, recently replaced SOS 275 clutch by previous owner (500 miles ago). I have owned 3 NSXs and never had this problem before.

When driving, if I somewhat lug the engine (ie 30 mph, 3rd or 4th gear, 2k RPM) and apply throttle, there is a grinding noise/metallic oscillating noise coming from the left/driver's side of the engine compartment. Same thing happens around 40-50 mph if I am in 5th or 6th and try to accelerate. Once I let off the throttle it goes away. If the car is not in gear and I rev the engine, it does not make the sound. If I keep the RPMs high by downshifting and then try to accelerate, it does not make the sound. Only when it is lower RPMs 1500-2500 and under load does it occur. No weird smells, no smoke. As far as I can tell, the clutch doesn't slip. I have put it in 5th or 6th gear going 40 mph and pin the throttle and the clutch does not slip.

At the time the clutch was done, the following were also done: MTF fluid, clutch fluid, TB/WP, crankshaft rear seal, drive axle seals.

My other two NSXs sounded normal, this is definitely an abnormal sound.

Any ideas? Thanks!

 

[Old Guy]

I do not know what the answer is; but, I might be inclined to drain the transmission fluid and see what comes out. If nothing other than oil come out (a good thing) you should be able to put it back in (minus spillage) since your records indicate that it is new. Pull the transmission filter and inspect. Inspect the left driveshaft while you are down there.

New clutch, rear engine seal and driveshaft seal in less than 30,000 miles? Did this car have some heavy use?

 

[cyanutopia]

No, it actually was barely driven 1000 miles in the last 10 years. The previous owner was very OCD about his cars and did a lot of preventative maintenance. This car has definitely never been tracked or driven hard.

Thanks for your thoughts though, and may consider doing the fluid change if I can't find another alternative option.

 

[asylum]

I would check the drive shaft. At least regrease them.

 

[cyanutopia]

Thank you - will do.