spl subframe spacers + R.P. 75w90 + 180sx vlsd = humming noise, grrrr.

[nissan_star]

I just put in a 4.3 final drive jdm 180sx diff and spl alum. subframe spacers. I filled the diff with Royal Purple 75W-90 Max Gear with lsd additive.

My problem is a somewhat high pitched humming/buzzing noise that increases as rpm increases. It does not happen when I am not using the gas or when I am coasting, only when I try to accelerate. This makes me think that it is not a wheel bearing, but what the F do I know.

The Royal Purple fluid seemed really thin, the stuff that came out of it was much thicker looking. The new diff does feel smoother then my old open diff did.

Also, I do realize that the subframe spacers will add noise, but I dont think this is normal.

I don't know what else to say, thanks for looking.

[nissan_star]

no help from anyone?

[jdm_master_X]

i know this might not be useful, but im running the exact same setup with the exception of me running the actual spl aluminum bushings. it sounds like a supercharger as RPM increases, and has gotten increasing louder as time progressed. i guess you should get used to it. :P

[MICRoS13]

Wheel bearings i saw it on the show how there was a humming sound and they replaced it and the sound went away idkk i might be completly wrong

[gumby74]

I went through the same issue with my setup, save I am running a helical diff and using Castrol gear oil. Same issues with the humming noise. However, after I assembled the housing I had the backlash inspected by a gear shop. Everything was well within spec, so I am not to worried about the humming. I did discover the addition of an aluminum driveshaft greatly decreased the humming.