Hi Joel
You just need to have it re-shimmed, it's considered normal maintenance for plated LSD. Tony Flood has done mine in the past by measuring the load that it breaks free at and shimming to suit your chosen application.
For diff oil try Castrol SAF-XA approx $32/L comes with friction modifiers already added and is arguably one of the best LSD oils on the market.
If you like to change your oils often then you could go a much cheaper product. Around $30/4L I used Castrol LSX85W140 for several years in my Kaaz. LSX85W140 was recommended to me by a WA Diff and Transmission specialists whom have proven it for many years in hipo LSD applications.
Btw, great thread steal with parallel discussions, you gotta love Perth - WRX
