The nearest grain bed auger to the access panel or on the left of the combine, stopped turning. We found that is is moving forward and aft an inch or so. when it moves forward, it will not engage with the gear that turns it. If you push it aft, it will turn. Looking at the parts breakdown, we are not seeing why this auger should be shifting forward and aft. None of the other five move at all. We really don't want to take this out as most of us are too fat to get to where the gears are located. We would have to remove the sieves to accomplish that. Any suggestions as to why this one auger is shifting?