automatic gearbox oil change needed or not?

[codered]

Dear Sirs,

I have a x5 4.4i,2000,147.000km
My car mechanic insists the automatic gearbox needs an oil&filter change.
I know the x5 book says it's lifetime guaranteed and doesn't need changing,however I've heard opinions from the mechanics saying that if the oil is not changed,the automatic gearbox will fail sooner that 200.000km .They claim to have 3 X5 gearboxes failed due to old automatic transmission oil .
So , should i change the oil&filter of the automatic transmission or not? What oil should be used for this?
I'd appreciate some professional feedback if possible.