I sure you have ck the motor break. There is a lever on the motor when in the lock possition the motor will only move the chain when it is power is on. If you don't have the owners book then ck the internet. Good luck and let us know what you have found.[b][/b]
My rear bed in my XT276 also drops when traveling,thankfully I noticed this before I put my bikes in.I have put slide pins in holes on bed tracks to stop the bed from dropping,just remmeber to remove before you lower the bed.