Any help would be greatly appreciated! This has been a hay tractor for the past 10 years pulling a 9 ft disc mower and 851 NH baler. Have had no issues even in the thickest crop. The other day was pulling a woods 214 batwing through dry horse weed stubble just cleaning up the pasture ( so no load on the PTO) and the PTO just slowed to a stop as though I had put the lever in the neutral position. H & L on the PD works as it should and power steering works with normal "creeping." I changed all hydraulic oil and still in "neutral!" No matter what the PTO lever position, I can turn the shaft in the rear by hand. It turns smoothly. Tractor does not have the external lever under the battery box that I have read about. I have heard a few ideas by asking around... Coupler? Clogged Hyd. PTO valve? Broken PTO shaft? I would really like to start off as least invasive as possible! Open to all suggestions! Thanks Y'all!