SO I replaced my noisy diff...with one with 90k.

[Sean]

...and now my new one is making noise. WTF?

My old one whined ungodly loud, any gear any speed, just a constant whine that got louder with speed.

Right away after putting my 3.73 LSD with 90k in, it was making very slight repeating noise - it's not constant, Whine...whine...whine...whine. Then when I speed up, it gets faster. It's gotten louder over the last 1500 miles, and now it's really beginning to piss me off, because changing that huge block of steel wasn't f-in easy.

Could it be my halfshafts? Or, is THIS diff making noise now??? It's running 75w90 Redline diff fluid, nice and full and no leaks.

I'm seriously fed up with my car. ugh.

[drift]

did u have a chance to open the rear cover ? see if there's something wrong in there, such as metal shavings etc.
do you remember if the old diff fluid was like pitch black?

[E30 Racer]

Are you using a solid diff mount and/or urethane transmission mounts. Both *will* contribute to your ability to hear the whine.

[kenika65]

Damn you having hell with your car. Does it wine in reverse if not then I would suspect a bearing gone bad. Well good luck.