Theres lots of stuff mate, in the service book its all in there what they do etc. Also the e39 autobox dont have there fluid changed as they have lifetime warranty or something, but people recommend you to change it around the 100,000 miles mark, how many miles has yours done ?
Just has my autobox serviced on my 530d - mileage is 62k, they are sealed units which according to BMW have a life long oil - but then they would say that - so when it goes bang they can prime you for a four grand bill for a new autobox. My autobox man recommends a box service at any point after the 60k mark then 24 mnths or 25k intervals. The problem with autoboxes is that when they begin to play up the damage is done and you will have to pay out to get it sorted - best to get done just to give you piece of mind.