Castrol SP 320

Is it OK to use it in the Gearbox and Diff of a 300tdi?

Look at the specs on the Castrol site it's a mono grade sae 95 oil so depends where u r in the world.

I am in good old blighty

Should be ok for axles & transfer box, but NOT gearbox. R380 g-box runs on ATF. (Yes, a manual box that runs on DexronII or DexronIII auto fluid)

Thanks for the help. As an oil for the transfere and diffs how highly would it be rated?

Just been on the Castrol site and can`t find SP320 approved for any road/truck uses?? If it`s an sae95 gear oil I`d say it`s slightly heavier than the recommended, but....
Looked again and seems to be for industrial gearboxes. Maybe ok, but no guarantees. If you`ve got freebie then maybe use it??