Trouble Hooking Up Trailer due to "Gear Slack"????

When I get about 2 inches away from the hitch I lower the front of the trailer so that the tongue is about 1/2 lower that the ball on the WDH. Then back up real slow and when the ball gets into the socket on the tongue you can put the truck in park and the truck won't move. Then the ball is already lined up and all that has to be done is lower the hitch and lock the lock. Been doing this for 6 years and it works every time.