1965 MF135 PTO issues

When engaging the pto with no equipment attached it goes in and disengages fairly easy with little to no grinding. However as soon as any equipment is connected it is extremely difficult to engage the pto and even harder to disengage. And when disengaging the tractor jumps forward about 3 feet even with the tractor in neutral. Any and all advice would be greatly appreciated.

Hello, that’s an interesting problem. Are you pressing the clutch pedal
fully when you disengage the PTO? The first step would have to be
partly draining the trans oil to a point just below the bottom bolt of the
left hand side cover. Remove the cover. Check for signs of wear on
the end of the lever. There is a groove for the lever to engage in on
the bottom (PTO) gear. Check that this is intact. Looking upwards
inside using a flashlight make sure that the split pin in the coupling is
in place and that it cannot move forward. Next check that the pinion
gear is secure and cannot move forward when you disengage the
PTO. Check the condition of the teeth on both gears. Any burring on
the teeth will make it more difficult.
The hydraulic pump is secured by a dowel under the small oval plate
on each side. Drain the remainder of the oil and remove the dowels.
It is possible that one or both dowels have broken and allowed the
pump to drop out of line slightly. If the dowels are ok check around
their location point in the front plate of the pump. These break
occasionally. If the pump is out of line that will certainly make it
difficult to operate the PTO lever . Let us know what you find.
DavidP,South Wales