3.8 Moss Gearbox Oil (second time around)

[Philk]

It is now 6 1/2 years and six thousand miles since I put Redline MTL into my 3.8 Moss gearbox. Aside from the well-documented propensity for this to seep more around the seals than higher viscosity oil (never enough though to warrant topping up the gearbox), I have noticed the gearbox has got a bit stiffer this season and, extracting a bit of oil from the gearbox, I can see it is now yellow as opposed to the pale pink colour the oil was when it first went in.

I'm therefore considering a gearbox oil change and thought I'd reach out to the Forum for the latest thinking from the great and the good present here. Noting the Moss box does need different oil than the 4.2 all synchro gearbox, has anyone tried Castrol Classic XL30 SAE30 mineral oil. Any other recommendations?

[Jagboi]

One of the Jaguar saloon forums has a Tribologist (oil/lubrication engineer) on it, and his recommendation for the Moss is a synthetic SAE 30 engine oil.