3-Point Hitch MF2660LP Heavy Clanking Noise

[JWR]

When the 3pt position control is near the top (near but not in the constant pumping area) one can produce an horrendous clanking noise that resembles or exceeds the worst rod bearing noise you ever heard. Initially I did not know it was dependent on the position control and was near panic on a new tractor with under 50 hrs on it. An experienced mechanic (not on tractors) said "shut it off and haul it to the dealer quick!"
Eventually I discovered it was only when the control lever is near but not in the constant pumping region.
I have a very plausible explanation from one service manager and a puzzled "I don't know" from another very senior service mechanic. The Massey rep has yet to comment. I'll pass on what we think it is after I hear some comment.
Anyone out there familiar with this disease ?

 

[PoorPlowboy]

Low hyd fluid level or faulty pump?

 

[JWR]

Low hyd fluid level or faulty pump?

No. The fluid is right on full. I am certainly concerned about a possible faulty pump but the tractor only has 60 hrs on it now. One service mgr tells me he has heard it before and explains that the 3pt pump is on a shaft. It rocks on that "keeper shaft" based on torque from load or position. When it gets up close to constant pumping it encounters a spring which gets compressed as you move the lever into constant pumping territory and that triggers the bypass valve to avoid damage. If you are just barely to the spring point it can oscillate back and forth "between bypass and not bypass" with the pump rocking back and forth on that inherently loose fitting shaft. That produces the noise (he says.) I'm looking for other owners and/or people experienced with these machines.