2000 , X Reg S3 DeDion 45k on the clock and shes living in hot , dry sunny Spain .Type 9 gearbox , presume Sierra open diff at rear .
So , 75 / 90 GL4 ( not GL5 )but Castrol do a GL 4+ for the Gear box
What to put in the rear diff ?
Both are sealed for life and just need topping up so I'm told .Sorry , I like to change on a regular basis .
Ant thoughts ?