Mine came off....the u-joint itself can go on the drive shaft either direction at the output end of the motor. the differential end of the drive shaft has a spring inside the cup, it goes in the differential. most u-joints won't come off the drive shaft, but every once in a while I see they come off.
slide it back on the output shaft, and make sure the spring is in the cup end that goes in the differential ?. this is what keeps pressure on the output shaft and u-joint.Mine came off....the u-joint itself can go on the drive shaft either direction at the output end of the motor. the differential end of the drive shaft has a spring inside the cup, it goes in the differential. most u-joints won't come off the drive shaft, but every once in a while I see they come off.