Note. Adjustment must be carried out in the specified order, since the torques of resistance to rotation of the bearings are adjusted taking into account the torques of all rotating parts of the gearbox. Before disassembly, if the bearings are to be reused, measure and record the torque resistance of the bearings that must be sustained during reassembly. Bearings must be lubricated with gearbox oil.
When adjusting the outer race of the rear bearing (pic. 4-72) must be installed and minted. The selector lever lock cable and parking brake gear must be installed.
Install two adjusting rings, each 1.5 mm thick, on the drive pinion shaft. Install the final drive driven gear onto the final drive pinion end and tighten the hex nut «at 41» torque of 25 kgf·m by applying the parking brake.
Attach the indicator stand to the gearbox housing (pic. 4-73). Put a mandrel on the end of the drive pinion shaft. Install the indicator on the stand so that its leg rests on the mandrel with a preload of 1 mm. In this position, fix the indicator and set its arrow to zero. By moving the drive shaft-gear up and down, determine its axial movement by the indicator, which is, for example, 0.93 mm.
Warning. When measuring the axial displacement of the main gear drive shaft, do not allow it to rotate, because the self-alignment of the bearing rollers during rotation violates the measurement.
According to the formula S=A- (B+C+D) calculate the thickness of the adjusting ring of the main gear drive shaft bearings, where:
S is the thickness of the adjusting ring;
A is the total thickness of the adjusting rings;
B - the value of the axial movement of the main gear drive shaft;
C - the value of the preload of the bearings of the main gear drive shaft;
D - the value of self-alignment of the bearing rollers of the main gear drive shaft.
Example.The thickness of the adjusting rings is 3.00 mm, the measured axial movement of the drive pinion shaft is 0.93 mm. the value of the preload of the bearings of the drive shaft gear is 0.12 mm. the self-alignment value of the bearing rollers is 0.10 mm. S=3.00- (0,93+0,12+0,10) = 1.85 mm.
Refer to Table 4-9 to determine the thickness of the adjusting ring.
Remove final drive driven gear and adjusting rings. Install the selected adjusting ring on the final drive pinion shaft.
Install the final drive driven gear, screw the nut onto the end of the main gear drive shaft and tighten to a torque of 25 kgf·m. then lock the nut by pressing the holes on the neck of the nut. Put the head on the nut «41» (pic. 4-74) and using a dynamometer, measure the moment of resistance of the bearings to turning the main gear drive shaft, which for new bearings (lubricate the bearings with gearbox oil before installation) should be within 0.8-1.2 Nm.
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