Been looking on opie oils and ive found the castrol gear oil suggested in the how to guide in articals.

But its semi synthetic can fully synth be used? just i spotted this and wondered if it was any good?

http://www.opieoils.co.uk/p-850-silk...-gear-oil.aspx

and this is the castrol one

http://www.opieoils.co.uk/p-744-cast...-gear-oil.aspx

This is the full list available in 75w90, any others people have used and tested?

http://www.opieoils.co.uk/c-673-75w-90.aspx