How do I change gearbox oil - 2001 Jaguar S-Type

If its the zf auto box drain the fluid from the plug in the sump pan when empty refit plug remove level plug from rh side of gearbox. 8mm allen screw, yust above exhaust, refill with correct fluid through that hole,run engine get transmission oil temperature to between 50 - 70 degees C you need temp probe to do that or jag diagnostic gear or you can guess by feeling transmission sump pan. work the gearshift through all gears. then remove level plug allow to drain if level to high or top up if low, make sur you use the correct fluid, hope this helps