and the clutch drum f d in an unmodified automatic transmission as shown in fig1 through 13 is through the holes 76 78 past the balls 77 79 the ball is held in place by a staked portion 72 of the side wall of each hole 76 78 which is caused to extend towards a center of the hole 76 78 on a side of the hole 76 78 adjacent the clutch piston 100 150 this movement of the wall of the hole 76 78 is usually caused by staking the hole 76 78 with a tool which causes a portion of the side wall of the hole 76 78 to be distressed and relocated closer to a center of the hole 76 78 therefore hydraulic fluid may pass from a side of the clutch drum f d opposite the clutch piston 100 150 through the hole 76 78 and past the ball 77 79 when sufficient hydraulic fluid passes past the ball 77 79 to force the clutch piston 100 150 away from the clutch drum f d a different gear ratio is selected which decreases load on the engine causing the velocity of the engine to decrease and hydraulic pressure created by the pump to decrease which applies the clutch piston 100 150 the hole 76 78 has a necked down portion on a.