Gotta 1056 that has been stalling during operation a few weeks now I havent been to track down the cause..then today it twisted the yoke out of the rubber isolater inside the shaft.. Transmission issue? Or converter clutch locking up intermittent??
When you say locking up it like the hydraulics are dead heading and Stalling out the engine ? Did you have any driving issues before ? The hydraulic pump receives its power out of the output shaft of the transmission. If the machine was driving fine and was not jerking or trying to lurch with it in gear but not moving or had no problem untracking and getting going i would maybe lean more to the hydraulic pump first. Could be converter but i would think you would have felt some drive issues...