6th Step (See Fig.3-9 and Fig. 3-10)
While passing through the block ring, the mesh sleeve shifts by a distance of Y, shown in Fig.7 and the chamfers of the mesh sleeve spline (6) come into contact with the chamfer of the spline (6) (See Fig.3-9). Due to the contact of chamfers, the torque Tc turns the gear (11) over an angle relative to the mesh sleeve and meshes the mesh sleeve spline with the spline (6).
Until now the complete synchronization course is over and then the power is output through the main shaft, clutch hub, mesh sleeve and gear (11).
In neutral position —
The power from the driving shaft (1) is transmitted through the input gear, the cluster gear (3) & (4) to the high speed gear (6) or low speed gear (11). Due to the mesh sleeve is in the neutral position, the main shaft, output gear and output shaft are not rotated so the power is not transmitted to the high speed or low speed gear,
Gear shifting —
When the shifting lever is operated, the shift fork moves the mesh sleeve to allow relative gears to mesh through the synchromesh mechanism. Power is transmitted in the following order:
Driving shaft-Input gear-Cluster gear-High (or low) speed gear-Synchromesh mechanism-Main shaft-Synchromesh mechanism-Reverse (or forward) gear-Output gear- Output shaft.
Power flow in forward 1st speed gear position: 1-2-3-4-11-10-8-9-12-16-15-17-18-5-21
Power flow in forward 2nd speed gear position: 1-2-3-6-7-8-9-12-16-15-17-18-5-21
Power flow in reverse 1st speed gear position:
Power flow in reverse 2nd speed gear position:
1.3 Reduction Gear (See Fig.3-12)
The reduction gear located in the front of the transmission is used to reduce the speed and increase the torque from the output shaft of the transmission and impart them to the differential. It consists primarily of a small spiral bevel gear on the output shaft and a pinion shaft splined with a big spiral bevel gear. Both ends of the pinion shaft are supported by tapered roller bearing. Several shims are installed between the case and bearing covers to adjust the clearances between them.
1.4 Differential (See fig. 3-12)
The differential is housed in the front portion of the case of the differential the front end of which is connected with the axle housing. The differential case is of splitting type. The differential includes two half shaft gears and four planet gears. The thrust washers are installed between the differential case and each gear and between gear pairs to keep a proper clearances between them. The planet gears are supported by planet gear shaft Ⅰ and Ⅱ . The shaft Ⅰ and ring gear (1) are fixed to the differential case respectively with knock pin and bolt.
The power from the transmission is transmitted through the reduction gear, differential, half shaft gear and half shaft to driving wheels.
1.5 Removal of Shift Forks
The figures from 3-13 to 3-20 show the removal procedures of the shift forks in the drive unit which has been removed from the truck. The procedures are also applicable to the removal of the shift
forks under the condition that the drive unit is in the truck.