I have dug over 30 large stumps & a couple 1000'of large ditch useing the cutting edge of bucket & getting the front tires off ground as to use the front end wieght of tractor for digging & just wiggle it ever so slightly & curl. I have no bent anythingon my 3000 series JD. If ground is rock hard forget it. or do it in spring. Just gently let the tractor come back down on it's front tires. I have watched my masterfull neighbor do this with JD tractors for 30 years on stumps or anything else you can imagine. His tractors run as new,none have broke a cylinder or messed loader up, just make sure if you distribute load evenly across bucket cutting edge. If you hook a root on a corner just gently let off. I have put in alot of colverts also with FEL, in fact it is all I use for that task. My dad used to do this also with a little JD 750 & no problems, this is were light tractors might be a plus, as in just enough to dig, but less likely to tear something up.People will say just get a backhoe, easier said then done in real world sometimes as far as $ avalible when these projects arise.
Joe