I think I was finally able to resolve the squeaking flail mower but not before heading down another rabbit hole. I run the Del Morino on the back of the MX which has a PTO rating of 51.8hp. When reading the owner's manual this morning I noticed that it states (in Italian English) ...
"Maximum power applicable to the gear box: 22 Kw +/- 5% with 540 r.p.m. Superior power to which is indicated can damage irreparably the transmission gear box; especially during heavy works."
22Kw is about 30hp so I was starting to think that maybe the MX is too much tractor for the Centurion Super 158. So I look at Del Morino's website, and on the same page they state a range of 30 - 70hp and 15 - 60hp for the model I have. I looked at GWTC's website and they have a Del Morino specifications table that shows a range of 30 - 70hp. We've all encountered errors in owner's manuals so I have to think that whoever worked on the manual used the spec for the smaller two-belt drive models which have input ranges of 15 - 35hp.
So back to figuring out the noise. I ran the mower with the belts off and was able to determine that the noise was either coming from the gear box or the main pulley bearing, which is a sealed bearing. That bearing is kind of odd since it's not pressed onto the pulley spacer that goes inside it. To be honest, it kind of acts like a spacer as far as I can tell, or on second thoughts it supports the output shaft and reduces the bending moment. Anyway, I pressed out the old bearing and installed a new one that GWTC shipped to me at no charge. I still think that the gear box makes more noise than it should, and I don't know if the gears are straight cut or helical (which could affect noise), but the oil level is fine and according to the manual is good for 500 hours. I might still change the gear box oil this weekend, spec is 140W, but the flail is definitley quieter than it was and that's standing next to it when it's running at 540rpm. From inside the cab it's back to making a normal humming sound at full speed.
Well done to Del Morino for making the pulley in such a way that the bolts that clamp it to the output shaft can be used to press if off the shaft. The pulley is secured to the shaft using a conical collar that tightens around the output shaft as the bolts are tightened.
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Pulley spacer and conical clamp.
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This is the bearing that I replaced.
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Gear box output shaft.
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Pressing out the old bearing.
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New bearing installed.
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