Dodge

My friend has a colt vista wagon, 4x4. when she shifts into 5th gear, it seems to stay in 4th. rpms and speed do not change. also, her back-up lights dont work. is this an electrical thing, or is it the 5th gear servo? if it was a servo, wouldnt it be like having it in neutral? thanks for help, i dont know anything about dodge...lol

I would like to point out that a dodge colt is a re-badged mitsubishi. wanted to straighten out the record before someone got the idea that dodge makes inferior transmissions......oh, wait.......