I have a 2006 4.4 and experience the same conditions. I have learned to make a complete stop before accelerating when on a hill. But, sometimes it is just not possible. I have read on similar posts, that this is somewhat normal for the ZF 6-speed automative transmission.

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Current: 2014 X3 35i, Titanium Silver, M Sport, Cold Weather, Premium, and Technology packages.

Previous BMW: 2006 X5 4.4, Stratus Grey, Nav, Sport & Cold Weather packages, BMW Running boards, Intravee II, Michelin Latitude Tour HP.