I don’t often find myself changing transfer’boxes on Defenders, but this month I’ve had five to do in quick succession for various reasons, and have become thoroughly acquainted with the internal workings of the LT230 in its various forms. This design is one of Land Rover’s unsung heroes: introduced in 1983 for the then-new One Ten, it remained in production through to the last Defender Puma, as well as providing awesome off-road capability to the first and second generation Discovery.
The LT230 is a strong and simple beast, combining a two-speed gearbox with a lockable centre differential, all controlled with nice simple levers and no electronics. As people have found, it will handle a good deal of abuse and far more power than any standard Land Rover engine: people are running them behind Cummins 6BT turbodiesels and they seem to survive for a while, at least. The thing which usually kills them is lack of oil, which I will come to shortly.
The LT230 was progressively modified and upgraded by Land Rover throughout its life, and the type of’box fitted can be identified via the serial number – two numbers and a letter (eg 22D) at the start, and a suffix letter at the end. Suffix A and B’boxes (model LT230R) had plain roller
