Originally Posted by SenorFunkyPants
Doing anything other than the BMW recommended change of diff oil would not be wise...especially adding aftermarket slip additives.
It's not aftermarket. It's warranty-covered service done at the dealership, using a BMW-created-and-approved additive.
Originally Posted by gr8000
I never had the diff noise - my car is a Jun '08 delivery with 15,700km.
As a matter of curiosity, are there any drawbacks when using the diff additive? If for instance will the discs slip smoother after using the additive (thus getting rid of the irritating sound), which could lead to a different LSD performance / behaviour?
As far as I MYSELF know, there is no change in performance, although you cannot perform differential oil services WITHOUT the additive from the time that you put the additive in.
If you drive it hard (AKA enthusiastically in a demanding, winding road) it should make a rapid ticking sound, like when your body is full of static electricity and you touch something metal over and over. If you drive it slowly in a tight circle with your steering wheel fully locked in a parking lot (or parking structure, the enclosed area will help you hear it) it should make a groaning sound, like the sound that sinking oil tankers make in movies. Try that if you WANT the noise.