Synchromesh Gear Box adopts spiral bevel gear transmission. The body of the box is separated into upper one and down one. It uses the spiral bevel gear adjusting device with compact structure. The assembly and adjustment is convenient and its reliability is high. The gear box also adopts forced oil lubrication which integrates lubrication cooling system and gear box. Therefore, the maintenance is more convenient. This type of synchromesh gear box has the advantages of compact structure, convenient adjustment, safe and high reliability, low noise and long service time.