[NextPerception]

I've actually modeled up the whole motor gearbox and did some FEA analysis of it in solidworks cosmos. I had to gues what alloy of aluminium the ring gear was but other than that it is dead on accurate. I came to the conclusion that it wasn't strong enough because there is a gear carrying plate that binds and rubs with the other stage of the gearbox ( i think this is why they stopped selling the 3 stage versions of this gearbox) that eventually tears itself apart. The FEA analysis indicated this problem and so I opened up one of the motors that had some running time under its belt and low and behold, stress fractures and deformation already starting at one end of the plate. I slow the process down with a pillow block supporting the opposite side of the shaft but it is still like a ticking time bomb. To tell you the truth, I wouldn't expect anything better at the price they are sold at.

Unfortunatley, Knowing what the problem is only half the battle. I don't have the capabilities to machine a gearbox inhouse or the funds to outsource it and so I am stuck finding an off the shelf part that fits my needs.