On my 1999, 3320 when I pull the PTO clutch handle, I cannot get the PTO engaged. (Grinds) I have adjusted the linkage as much as I can. Still no luck. I have tried dropping my rotary cutter into thick hay to bog the tractor with the PTO clutch pulled to release. Hoping to unstick it. No luck. I really do not know how this clutch works. Any help would be greatly appreciated.