Reverse Kicks out

Hi, I drive the truck listed above that has not had reverse in about a year since I have owned the truck. When you shift in to reverse and let the clutch out it will kick the shifter back to Neutral as well as if you hold the shifter in gear it will start to move and then jump and make a terrible grinding noise. Surprisingly through all of this if you are very easy on the clutch it will still slightly move backward but you cannot let the clutch fully out trying to find a starting point before I drop it.

Thanks.

ACC