Auto Box oil change for X7 (2010) - info. needed, please.

[rmunns]

I have tried on this forum to find something about changing the oil, but haven't.
I have now had this car for 2½ months / 6000km. The car has 201000km on it. I do have a little history, but do not know if/when an oil change for the auto box has been done.
Can please someone advise: What are the signs it needs doing? Roughly what's the cost / type of the oil? Is there a filter? is it a DIY job (what's the most difficult bit)? Does anything need doing to reset anything?

[SaabC5]

Signs it needs doing, lumpy hesitant gear changes. Thuds into gear from cold. You can tell a lot about its condition from smelling it and also the colour. It should smell sweet and also be translucent in colour. If it smells burnt, is grainy between the fingers and has gone dark brown/black its time for a change. You can't DIY it in one go either because 1/3 of the fluid will be in the torque converter so several changes are needed to get the vast majority of the fluid changed.