I am running a Woods backhoe on my tractor, and it has worked great for 5 years, but today the PTO started disengaging and re-engaging intermittently. It will work for 20-30 seconds, then go off for 10 seconds or a minute, and do this over and over. I thought it was due to adding torque with heavy loads, or related to the suction hose getting kinked a little, but it continued even after I re-positioned the suction hose to stay unkinked, and also when I was just putting the implement back into its neutral positions. The PTO engagement lever on the tractor seems fine, and the lift and drop hydraulic mechanism on the three point hitch seems fine, I have found that those can stop working when the tractor is tilted nose down, and I have to add hydraulic fluid to the rear axle housing to make them work again. Is this something related to the hydraulic fluid in the rear axle? Does the PTO need more oil to stay engaged just like the lift and drop mechanism does? What about the F->S lever on my right side, is that supposed to be in F position to deliver the most torque?