The original transfer box sump plate, while still perfectly serviceable, is being replaced with a more modern version. The gearbox is made of an aluminium alloy and the original sump cover from sheet steel. As the gearbox heated up though normal use, the alloy casing and the steel sump cover expanded at different rate. This lead to differential expansion and oil leaked out… even with a gasket in place.
The replacement item is from Rocky Mountain spares in Canada and is die-cast aluminium. The gearbox case and sump cover will now expand at the same rate and the likelihood of oil leaking out is reduced and with a generous application of some Loctite sealant, eliminated entirely…. fingers crossed.
The fins on the sump cover also act as a heat sink and help to keep the oil in the transfer box cool. This is a good idea for Land Rovers running the popular 200 / 300 TDi conversion as a turboed engine, with its additional power, will increase the operating temperature of the oil in the gearbox. I principally want to eliminate oil leaks but with the additional power that the Tuner Engineering motor will turn out, its not a bad idea to keep things cool back there.