6.6 03 3500 dully... Engine light came on and took it by autozone and they got a P0708 saying it could be failed transmission range sensor or open circuit condition... Should I be worried about driving my truck around until I get it fixed? Which one would it most likely be? Also when I switch down to 3rd 2nd or first it throws a code and won't go only works in drive? What do I need to do any help would be great!! Thanks