SO I too just had my ZF6HP26 valve body (separator plate B052) replaced by a new unit from RevMaxconverters.com and it too has made my tranny new. I have owned this x5 for 10 years now and It's never shifted this smoothly. I barely notice it moving about honestly. SO GLAD I went this route.
Perhaps the upgraded aluminum, instead of plastic bits, will help but I don't care as long as it lasts. Expensive but built properly and has 1 year warranty as opposed to me buying the ZF kit and repairing and if I had screwed up something badly, I could be back to square one repairing again. Buying this and returning my core (free, since they include a UPS core return sticker) was smarter and got my x5 back on road faster.

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I swear, my cars are like a girlfriend.
Sometimes its a rough ride, sometimes its smooth motorin'.
Sometimes she doesnt like how i treat her and sometimes i dont like how she behaves.
BUT at the end of the day, she loves it when I am inside her.

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'91 850i
'05 X5 4.4i
'09 Clubman S