Diff Snake oil?

[Singapore stag]

Hi, Any thoughts on whether to use a bit of Molyslip in the Diff when changing the oil? Stags usually suffer from a whining diff, loud as a mating Banshee. I used Molyslip in it once and it somewhat quiten down a little and also operated well, maybe a placebo......any thoughts, would it benefit the Z diff (longevity, performance)

 

[mmm-five]

Genuine BMW LSD (SAF-XJ-FM I think) oil has about 5% friction modifier in it - but it’s expensive from the dealer (about £40 for 0.5 litre and you need 3 bottles) for what it is, so most people go aftermarket and add a similar amount of FM to that.