Process depends somewhat on how many miles the fluid has on it. If the fluid has excess of 100,000 miles on it I would change the fluid 3 times. I would change the filter the first and third change. That means I would be dropping the pan twice. I would drive it about 25 miles between each change. If have transmission problems that are not corrected with first change it is unlikely addition changes will make a difference. Save a small amount of fluid from each change so you can compare to new and fluid from previous change. I only use ZF fluid but many use other brands with same specs.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas