You said: Haven't had chance to run PTO with a load,implement on it. So theres a different shaft for 1000 rpm. Didn't get a second pto shaft with tractor. 
Do you have implements that have the 1000 RPM PTO? I would think if you have one of those implement and you used it before you would have noticed the differeces in the PTO shafts? What implements do you have that are equipped with the 1000 RPM PTO. Around here they are few and far between. Many implements that have the 1000 RPM PTO will  need more horsepower than what the 1750 has. Example: the man the boy farms with has a large manure spreader. It is the only 1000 RPM PTO in their operation. It take 125 Horsepower minimum to operate. That is why some larger tractors only have a 1000 RPM unit.