I have a 750 Woods 16" bucket backhoe on a Ford Jubilee. It will dig 7.5' down.
To keep from breaking axles and housings I take some of the weight off the rear wheels with the outriggers (you need outriggers with cylinders on them and keep them tight on the ground ), this keeps the pressure off the tractor. This setup has a PTO pump. I just let the motor idle for most jobs. I am happy with this setup.