Hi,

My 2001 (X300 or X308 ? my french registration card says X 300), XJ8 is equipped with that funny ZF gearbox that is not meant to have its oil changed, but ought to have a $$$$$$ gearbox overhaul at about 100.000 miles.

At around 150.000 Km, mine began to behave in a rather unorthodox manner: engine emergency stop - style in the middle of the highway, funny dashboard messages etc.

Then, the Jag dealer in Limoges (France) told me the car was built for a maximum lifespan of 150.000 Km. I told the man he could keep his bovine manure to himself and drove back home, having the problem very 50 Km or so.

A friend told me about the same issues and had reduced the problem to the gearbox being the cause of emergency (safety) engine stops and funny dashboard messages.

I put my thinking cap on, looked up the type and # of the gearbox and called ZF in Germany (I am German).

The ZF people laughed. The OIL life span is indeed 150.000 Km for that particular gearbox. The OIL, not the box. They knew about some Jag designer who had specified a filled-for-life gearbox. They also added they had no idea of what that designer had been smoking but they were certain it must have been something really good. (My bet is Afghani Banana Peel).

The ZF guys told me that a special oil had been formulated for that box and that it was critical for ensuring the right amount of friction between non-touching, very close fitting friction disks. No other oil would work properly or not even at all.

That type of oil is manufactured by Mobil and is sold at a ridiculously high price outside France. I found it at 1/3 of the price in France.

Will post the oil specs as soon as I find that invoice back. Sorry.

I ordered a gearbox oil filter and an oil pan seal.

So, i drained the oil, let it leak out for half an hour. Took the oll pan off, got showered in black oil, washed the pan out. Took the filter off and installed a new filter. Put the oil pan back on. Using a garden sprayer, I over-refilled the box and got showered in clean oil (2 or 3 litres will not drain from the torque converter).

If you do this, repeat the whole procedure 10.000 Km later and your box is ok for the next 150.000 miles of good service.

Takeo.