Transfer box failure

A botched repair will always lead to failure – in this case needing a replacement transfer box, as Dave Barker explains

This Range Rover L322 needs a replacement transfer box. This is how it’s done...

This 2008 L322 Range Rover with the 3.6-litre TDV8 engine suffered complete drive failure after the transfer gearbox seized due to loss of oil. We suspect the oil had been leaking out of the transfer box for some time, unnoticed. The oil had leaked out through a hole in the transfer box case caused by corrosion where a steel transmission support insulator is bolted onto the cast aluminium transfer box. As the oil level dropped, the remaining oil would have become overheated and caused the transfer gearbox itself to overheat and then seize.

The transfer gearbox on the L322 Range Rover does the same job as on other permanent four-wheel drive Land Rover vehicles, in providing drive from the gearbox to the front and rear axles, while also allowing for the selection of high and low output ratio gears. Unlike earlier transfer boxes on the beam-axle Land Rovers, high and low ratio in this transfer box is selected and engaged by means of an electronic switch and motor fitted into the side of the transfer case.

Various options are available when thinking about replacing the transfer gearbox. A new box is listed by Land Rover Genuine Parts at almost £6000, aftermarket boxes (mostly reconditioned) are available at around £1800. In this case, a fully-reconditioned replacement exchange transfer gearbox was provided by a local independent ZF Automatic Gearbox specialist. The transfer box is used on a number of vehicles, including the BMW X5.