Finally got it hooked up. Talked to the dealer and he said to start the PTO on idle and take emery cloth and polish the PTO shaft. Then spray with lube and it should work. It seems that JD paints the PTO shaft and this can cause clearance problems on some hookups. Did as he suggested, sprayed it with WD-40 and it went right on. Have used the unit now about 5 time and it handles most everything I throw down the chute. A couple of times when I put a large diameter piece over 8 feet long it would start to slow down but it kept on pulling the material in and picked up speed as the diameter narrowed.
The only complaint I have is the brushes that guard the shredder opening are way too stiff. I've heard they will loosen up with use.
I'm glad I bought this unit as I have quite a bit of clean-up after the fires here in Southern CA. A lot of Summac, manzanita and sage brush burned off at the ground level. I am leaving the roots intact but chipping most of the stuff that went down because of the fire. The chips will help with erosion I hope.