check your drive axles i had same probem, i used scaner to watch wheel speed, and i looking for one wheel that is off any at all looking for what dose when i hit bumps, bad drive axle will do this, as i found out, i have replace bouth mine as rear drive axle went out , got new one put it in and it broke but this time the computer turn off the trasmission no park no nothing,I replaced the GIUBO "GUIBO" "Flex Disc" with one from URO parts (http://www.amazon.com/gp/product/B0066S2ROM/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1) , while doing my clutch. It seemed to be good quality and similar to the BMW one.
I followed the info I found on installing it correctly (Arrows pointing toward flanges, nut instead of bolt-head goes on back of flange, torque to spec from the nut end). It was a pain getting the two part driveshaft to stretch back to its original distance from the rear diff to the trans output, but no other issues. Even the driveshaft center balance bearing lined back up with where it was when removed.
I did convert to a single mass flywheel (lighter), so there is a little bit of vibration from rotation balance/gear chatter, but other than that I have no clue what the problem could be.
The fabric bands inside the guibo are starting to be pulled out in one direction. I attached a pic with the failure circled in yellow.
Any help is appreciated.
once i replace it computer restore control. it was admazeing that a computer do this to proteck the trasmission,
becuase drive azle could break the trasfer carse