For large-sized buses with the hydrodynamic retarder (the auxiliary brakes), because the structure of the propeller shaft connection (end yoke) is improper, the bearing stopper of the cross-shaped joint on the end yoke gets worn out with repetitions of starts and stops, or gets damaged at the time of assembling the propeller shaft. If left unfixed, this can lead to wobbly bearing, causing the propeller shaft to vibrate excessively. At worst, the bearing fixing bracket or fixing bolt breaks off, causing the propeller shaft to fall off.