Insane Hydraulics
Bold and audacious blog about fluid power
As you can see from the pictures, the damage to the cylinder block was not caused by over-torque (the splines are intact), but rather by shaft misalignment, caused by destruction of the tail bearing, and then the front bearing. This particular Caterpillar uses two motors for boom rotation, that's why the initial torque loss signals were masked up until the major failure occurred.
When you find your machine making strange noises or loosing force "just a little", don't let it reach the catastrophic failure point, do something about it, it will be cheaper and cause less downtime in the long run.