The ZF 6HP26TU/28 was used on the E70,
but only on the 4.8, until 2009, when the 8-speed replaced it for 2010,
and the X6 50i,
and possibly the diesel versions, as the 6HP28 was used on the X3 3.0sd high output diesel version only.
And the e90 335d, but not the 335i.

Also BMW referred to the 6HP28 as the 6HP26TU.
To retrofit the 6HP28 to a BMW that was fitted with 6HP26 would involve so much exhaustive reprogramming-

Not just simple coding that we do to enable some cool features to our BMWs!
If someone could do it, and was willing to go to all the trouble, might as well fit the later 8-speed...

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X5 E70 3.0d M-Sport , 2010 Titan Silver , ZF 6HP28, 320hp.

X5 E53 3.0d Sport, 2006 LeMans Blue, ZF 6HP26, diesel .