I have an 8 horsepower Troybilt Chippervac. I need to change the shredder blades on the flywheel and can't get the flywheel off; I've tried using a puller with the 3/8th 24 bolts in the holes in the flywheel. Haven't had any luck, can't get it to move at all. If anybody has any ideas, I'd greatly appreciate it. Thanks!