Sun Gear Failure in Second Round of Testing

A sun gear failed in the final drive system of a large tractor. Failure occurred in overload during field testing despite previous durability testing being successful. There was a change in induction hardening equipment between durability and limited production build, but the root cause was an underestimation of loading during original design which led to insufficient hardness requirements. These lower requirements allowed the shallower hardened parts to be used.