Re; Gearbox and Transfer Case Oils
The story went like this:
We ended up with the gearbox oil empty (don't ask ! ). When trying to find the refill oil we were made aware of the cost and even better still that none was available in Canberra, Sydney and Melbourne. The dealer service manager made the observation that this is the same box used in various other ( none Land rover) vehicles and that there is a Castrol oil used. At my instance he rang Land Rover and confirmed, in my presence,(speaker phones are marvellous) that use of this oil (invoiced to me as Castrol Transmax R ) would not void the factory warranty. I would suggest that you make your own inquiries before taking this path !
As far as the transfer case oil is concerned it is a Shell product that only Land Rover imports. It comes in one litre containers, boxed as Land Rover parts. Shell Australia denied any knowledge of it and I couldn't find any other local oil manufacturer that was prepared to offer a substitute.