I brought a Carlton SP5014 stump grinder several months ago. I only have 300 hours on it. But when the wheel is cutting and gets below the ground level, it gets jumpy and makes a banging sound. I thought it was the belts slapping against the cover but when I inspected it, I discovered the cutting wheel which seemed tight to the touch and spins freely and smoothly with no load on it, had a little play when you squeeze the belt together. (meaning, with the belt at normal tension is squeezed together creating more tension when the wheel is disengaged) I don't think there is suppose to be any play and am concerned it might be the bearing. The very edge of the poly chain belt seemed a bit worn making me think the pulleys may not be alligned properly, but then discovered the play in the cutting wheel so when there is a heavy load on the cutting wheel, it was pushing the lower bushing a bit higher. I just change the bearing myself, but the manual says you need to cut the drive shaft off to remove the bearing. Not sure I want to get into all that, but the closest dealer is in another state and it would put me out f business for a long time.