Rubbing sound/feel. HELP!

[E30Owner2025]

I’ve done quite a bit of wrenching on e46s and e30s but never taken a diff apart so I am all theory no practice there. The pinion gear makes nearly 4 turns for every one turn of the ring gear. The frequency of the sound leads me to think that the sound happens once every full wheel rotation. Could the pinion bearing make noice once every few turns?

[82eye]

I’ve done quite a bit of wrenching on e46s and e30s but never taken a diff apart so I am all theory no practice there. The pinion gear makes nearly 4 turns for every one turn of the ring gear. The frequency of the sound leads me to think that the sound happens once every full wheel rotation. Could the pinion bearing make noice once every few turns?

normally any sound the diff makes will both continue and increase in frequency with rpm. it shouldn't fade or disappear. a bad bearing will modulate but the sound usually does not fade out completely.

it's possible an axle, pinion, or rear wheel bearing is giving out, but i'd have to hear it to tell for sure. check the diff fluid carefully.

i'd also double check the lash when you reinstall the gears.