i had an 8 by 51 plugged tight as a nuns.......    with 27 percent corn once.  ended up taking the bearings off the end and hooking two tractors and pulling it apart.  It wasn't pretty as at first i only had a 5610 ford mfwd with loader as the "counterweight" tractor and it wasn't heavy enough to hold it and i could drag the whole thing with a bigger tractor.  I only resorted to this as i could not for the life of me get it to turn backwards even with a massive pipe wrench and a 6 foot cheater.    GOOD LUCK