Actually this is a well known problem with the X5, but BMW has successfully covered it up. It is regularly discussed here on the forum, but as soon as the thread pops up it is deleted.
Originally Posted by Stoubal
It is unusual that this has stayed up so long....
In snow country it is common to seen X5s clustered at the bottom of steep hills while other traffic passes them by...indeed, quite a few drivers have been cited for backing the wrong way up hills as well.
BMW should be embarassed.
Keep it as simple as possible...but no simpler.