For the differential unit of certain route buses of low floor type (also called 'non-step' type) , the torque of the flange nut may not be sufficient, due to an improper installation method, and the flange may loosen, in which case abnormal noise may be generated and/or the differential oil may leak. If this problem is left unattended, the propeller shaft may come off the differential unit, causing the vehicle to stall. Note: This problem is similar to the one submitted as RJ-0732-0 on 10th April 2001. The measures of the previous recall were not sufficient, so the new measures are submitted with this recall, with which the vehicles to be recalled are revised.