Hmmm.. Was told by some people to use
synthetic which I did initially ( castrol SAF-XA), but when I took the diff to a jag specialist which by the way is all they do, I was told to use Penrite Limslip 140 only unless I was racing then go something else of which I forget the name, reason for this was the jag setup is old technology and not designed for
synthetic oils. Unfortunately there seems to be a lot of differing opinions as to what is better which is I'm sure grounds for more discussion, either way I can't see how that would cause problems in such a short time just as you have said in your reply slowy!! Hopefully third time lucky, I am getting good at removing and installing the diff centre though.
