Forgive me if I am way out in left field on this but it sounds like when you put it in low or reverse the truck is actually in 2 gears. Try going into first since that is the gear it is hung in and then straight down into N and see if that works. Our old dodge use to be bad about not coming out of 5th but the shifter would be in N and that is how we fixed it. If you jumped the sift opening all together the only way to fix it is pull the stick and use a short bar and pull it out of 1st back into N, put the stick back in and away you go. Good luck.