there is a kickdown solenoid on the transmission too, make sure its not bad, and firstly make sure that the transmission is adjusted correctly which entails.

1 transmission fluid level correct (for dead cold 722.4, the level should be at the curl of the dipstick - not at the scale)

2 - pressure cable correctly set (zero pressure at idle)

3 - vacuum modulator correctly set. (incorrect causes slipping or super hard kick)

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)