I wasn't sure about the brake fluid either so I am using the Castrol GT-LMA in my 110. It's the stuff I have used in the Series 3 for years so no worries there. For engine oil I use ROTELLA T Multigrade SAE 15W-40. Used it with the 2.5NA engine and now the 300Tdi. After asking around it seemed to be the oil of choice for Land Rover diesels. While Synthetic oils may be nice in a harsher environments, I don't think it is all that necessary on an older engine like the 2.5NA in comfortable temperatures. As for the oil in the Roverdrive, don't quote me on it, but I am pretty sure it runs on 90wt gear oil, same as the Fairey and Toro overdrives. A quick email to Rockey Mountain will get you the definitive answer. 90wt also for the transfer box, swivel hubs, steering box and alxes. The main gearbox, the LT77, is best served with something like Redline MTF such.
Brett
Series 3 88 Diesel Soft Top
Ex-Mod 110 Tdi