NH 1720 tips dangerously to the right even on level ground. It is a 4WD with a FEL. Problem started a few months back when operating on wet ground while moving hay rounds but has gotten worse to the point that left rear wheel has come off the ground. Now it happens even when there is no load on the loader. Any thoughts on where the problem could be? Wheel, differential, axle? Front axle is on a center pivot pin and there is no discernable leakage or disconnected parts. Thanks! Any help is welcome.