The last time I went to shift into 4 hi or 4 low the lights flickered as if the shift was working but went back to 2 hi. The owners manual give an override procedure. That doesn't work either. I read on this forum a few posts that suggest disconecting the batery to reset the logic comand. Has anyone had any success with this? I can hear something what sounds like a relay when I attempt to shift but nothing else. Is this something that will set a code to help diagnosis? Any idea what code to expect?