ard, it's all up to you - personally I wouldn't change ATF at 45-50K miles. Many X5 owners here never bother to change ATF. Someone said changing ATF create more trouble for transmission.
Thirdy - wait... I may did a mistake here! Just checked my X5 and it has the climate control at the second row. I ordered it online BMW parts dealer after giving them my last 7-digit of VIN number. They told me part# is 11517586925. After ordering from them, I came to
www.realoem.com and check it via my X5 VIN number and it gives me the water pump part# too (11517586925), after reading your reply, this 11517586925 part# is without 4-zone climate control.
What year is your X5 and is it 3.0Si or 4.8? Mine is 2008 3.0Si with second row climate control and 3 row.
If you have a chance, try to access to
www.realoem.com and enter your last 7-digit VIN number then check your X5 water pump under COOLING SYSTEM, to see what's your X5 water pump part# and whether it is 4-zone climate control or not.
Thanks Thirdy.