The R380 box was introduced as brand new LR gearbox across the entire Land Rover and Range Rover product lines. The R380 is a radically reworked LT77 (The 1940's Jag gearbox remember) with improved main shaft bearing arrangements that provided an overall strengthening of the box. The R380 name stands for "Rated to 380 Nm input". But the R380 still has the LT77's 77 mm shaft spacing. Since Rover was no longer part of British Leyland the LT prefix was abandoned.
The V8 and Tdi R380 gearboxes have different bell housings and primary input shafts. They will interchange by swapping these parts.
The R380 quickly got a bad name from gear problems and accelerated main shaft spline wear where it mates with the LT230 transfer case.
The LT230 accelerated main shaft spline wear problem had been present on all previous LT230 equipped Land-Rovers, irrespective of the gearbox it was mated to. This design problem was kept low key until a lot of customers complained about R380 problems.
A number of different fixes, such as slingers and special transfer case input shafts have been added to try solve the LT230 problem.