This is amusing.The output never stops because the front planet is on,and the car is moving.THE REAR PLANET IS AN IDLER IN 2ND,THE FRONT DOES THE WORK.It is the front gear set alone that creates the 1.57 ratio 2nd gearthe problems encountered with the shaft are just like what is going on when an input shaft or drum breaks,the parts are loaded beyond the materials structural limitations.It has absolutely nothing to do with the application of the 3rd clutch.the high drum drives the rear ring gear from a stationary position to input speed rpm in hi gear.this locks the gearset together for direct drive.it takes the front planet out of reduction and locks it.