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Experience with RV8 gearbox and back axle oils
It has been a while now since Stuart Middlemiss (Nightfire Red 1215) from Norfolk changed the oils in both the gearbox (his has the R380 which was fitted to RV8s from VIN 0644 onwards) and the back axle. He thought it might be useful to circulate the results. (Jun 07)

Gearbox (R380)
As you may be aware, Land Rover changed the specified oil from ATF (very thin and watery) to MTF 94 sometime after the RV8 production run had finished. It's conjectured (but not confirmed as far as I know) that this change was to alleviate the inherent problem of weakness in the 2nd gear synchro usually experienced as a crunch when changing up from 1st to 2nd unless done very gently. Many drivers are in the habit of starting off in 2nd to avoid it.

However, the specification of MTF 94 is bettered significantly by Castrol's SMX-S fully synthetic 75W-85 GL4. This Castrol oil is very well regarded by enthusiasts on several Rover V8 forums and Geoff King, an authoritative poster of V8 and RV8 information on the V8BB, absolutely swears by it. It is said that the oil pump in the gearbox can well handle the slight increase in
viscosity.

So this is what I used. The capacity of the box is just under 3 litres. Result: gear changes are very slightly stiffer in the first 3 or 4 minutes of driving compared to the ATF which was still in mine, due to the Castrol being a little thicker, but beyond those first few minutes of warming up, the gear change is slick, the slight notchiness changing down into 2nd from 4th has disappeared and, best of all, changing up from 1st to 2nd is now as slick and crunch-less as all other changes! So it has earned my