Gearbox assembly (VAZ-2105)

Differential assembly

Install the axle shaft gears with support washers and satellites. Turn the satellites and axle shaft gears so as to align the axis of rotation of the satellites with the axis of rotation in the box, then insert the satellite axis. Check the axial play of each axle shaft gear: it should be no more than 0.10 mm. If the clearance is increased, which is a sign of excessive wear of the gears, replace the axle shaft gear support washers with others of greater thickness. If the specified clearance cannot be obtained even when installing washers of the greatest thickness, replace the gears with new ones.

Install the driven gear and press the inner bearing rings onto the differential box using the A.70152 mandrel. The mandrel is made of a pipe with an outer diameter of 43 mm and an inner diameter of 35.2 mm.

Installing and adjusting the drive gear

Having secured the gearbox housing on the stand, press the outer rings of the front and rear bearings of the drive gear into the housing sockets, using mandrels A.70185 for the front bearing and A.70171 for the rear (Fig. 135).





On mandrel A.70184 (Fig. 136), simulating the drive gear, install the inner race of the rear bearing and insert it into the neck of the gearbox housing. Install the inner race of the front bearing, the flange of the drive gear and, turning the mandrel for correct installation of the bearings, tighten the nut (tightening torque 0.8-1.0 kgf·m). Fasten device 2 (A.95690) to the end of mandrel 1 and adjust the indicator with a division of 0.01 mm to zero, installing its leg on the same end of mandrel A.70184. Then move the indicator so that its leg stands on the mounting surface of the differential case bearing. Turning the mandrel with the indicator left and right, set it to a position in which the indicator arrow marks the minimum value a ₁, and write it down. Then repeat this operation on the seating surface of the second bearing and determine the value of a ₂. After this, determine the thickness S of the drive gear adjusting ring:




where a = (a ₁ +a ₂)/2 is the arithmetic mean distance from the ends of the mandrel to the journals of the differential bearings; b — deviation of the drive gear from the nominal position, mm.

The deviation value is marked on the drive gear in hundredths of a millimeter with a plus or minus sign. When determining the thickness of the adjustment ring, take into account the sign of the value B and its unit of measurement.

Example. Let us assume that the value of a, set with the indicator, is equal to 2.91 mm (a is always positive), and on the drive gear after the serial number there is the number -14. To obtain the value of b in millimeters, the specified number should be multiplied by 0.01 mm, i.e. b = -14 0.01 = -0.14 mm.

We determine the thickness of the adjusting ring for the drive gear (mm):


In this case, it is necessary to install an adjustment ring with a thickness of 3.05 mm.

Place on the drive gear 29 (see fig. 128) adjusting ring 21 of the required thickness and press on the inner ring of the rear bearing, removed from the A.70184 mandrel, using mandrel A.70152. Put on the spacer sleeve.

When repairing a gearbox, it is necessary to install a new spacer sleeve if the gearbox housing, main gear pinions and pinion bearings have been replaced. If the specified parts remain the same, the spacer sleeve can be reused.

Insert the drive gear into the gearbox housing and install the front bearing inner ring, oil deflector, oil seal, drive gear flange and washer onto it. Screw a nut onto the end of the drive gear and, having locked the drive gear flange, tighten it (tightening torque 12-26 kgf·m).

Tightening the pinion bearings

To limit axial displacements of the pinion gear under operating loads, it is very important to create a preload in its bearings within the specified limits. The preload is controlled by a 02.7812.9501 dynamometer, which allows measuring the torque of resistance to gear rotation. This torque determines the degree of tightening of the bearings. It should be 16-20 kgf cm for new bearings and 4-6 kgf cm for bearings after a run of 30 km or more. The flange nut should be tightened to a torque of 12-26 kgf·m, periodically checking the torque of the bearings to the rotation of the pinion gear. To check the torque, place the dynamometer on the adapter sleeve and make several turns clockwise with the handle. When turning the pinion gear, the dynamometer's movable pointer should not go beyond the limiter and should show at least 16 kgf cm. If the torque resistance is less than 16 kgf cm (4 kgf cm for bearings after 30 km), then it is necessary to tighten the drive gear flange nut (without exceeding the specified tightening torque) and check the torque of resistance to turning of the drive gear again. If the torque of resistance to turning is more than 20 kgf cm (6 kgf cm for worn-in bearings), this indicates that the preload of the bearings is too high. In this case, it is necessary to replace the spacer sleeve, since it has deformed due to excessive load to a size that does not allow for proper adjustment. After replacing the spacer sleeve, repeat the assembly with the appropriate adjustments and checks.

Installing the differential box

Install the pre-assembled gearbox together with the outer bearing rings, two adjusting nuts 1 (Fig. 137) so that they touch the bearing rings, and the bearing caps into the gearbox housing. Then tighten the mounting bolts.



Perform the preliminary tension of the differential box bearings and the adjustment of the lateral clearance in the engagement of the main gear gears simultaneously using the device A.95699/R and the key 12 (A.55085). To do this, secure the device to the gearbox housing with screws 11 and screw them into the holes for the mounting bolts of the locking plates of the adjusting nuts. Move the bracket 4 of the indicator along the guide of the device until the lever 2 touches the outer side surface of the cover and tighten the screw 5.

Loosen screws 7 and 9 and install bracket 10 so that indicator leg 8 rests on the side surface of the driven gear tooth at its edge, then tighten the screws.

By turning the adjusting nuts, the lateral clearance between the gear teeth is preliminarily adjusted within 0.08-0.13 mm according to indicator 8 while rocking the driven gear 13. In this case, the bearings should not have a preload. The adjusting nuts should only be in contact with the bearings, otherwise the correctness of the preload measurement is disrupted.

Consistently and uniformly tighten the two adjusting nuts 1 and 2 (Fig. 138) of the bearings. In this case, the differential bearing caps diverge and the distance A increases. This divergence is noted by indicator 6 (see fig. 137), on the leg of which lever 2 acts. Tighten the nuts for adjusting the differential box bearings until the distance A increases (see fig. 138) by 0.14-0.18 mm. Having set the exact preload of the differential box bearings, finally check the lateral clearance in the engagement of the main gear gears, which should not change. If the clearance in the engagement of the gears is more than 0.08-0.13 mm, then bring the driven gear closer to the driving gear. If the clearance is less, move it away.



To maintain the set bearing preload, move the driven gear by tightening one of the bearing adjusting nuts and loosening the other by the same angle. To perform the operation accurately, watch the indicator 6 (see fig. 137), which shows the previously set bearing preload.

After tightening one of the nuts, the indicator reading will change as the distance A increases (see fig. 138) and preload of the bearings. Therefore, loosen the other nut until the indicator arrow returns to its original position. After moving the driven gear along the indicator 8 (see fig. 137) check the side clearance. If the clearance is not within the norm, repeat the adjustment.

After adjustment, remove the A.95688/R device, install the adjusting nut locking plates and secure them with bolts and spring washers. Spare parts include two types of locking plates: single- and double-jawed. One or the other plate is installed depending on the position of the nut slot.

Checking the contact of the working surface of the gear teeth

To check the quality of gear engagement:

• install the adjusted gearbox on the stand and lubricate the working surfaces of the driven gear teeth with a thin layer of lead oxide;
• start the stand and use its levers to slow down the rotation of the axle shafts so that under load, traces of contact with the teeth of the driving gear remain on the surfaces of the teeth of the driven gear;
• change the direction of rotation and, by braking, you get contact marks on the other side of the driven gear teeth, which corresponds to the car moving backwards.

The engagement is considered normal if on both sides of the driven gear teeth the contact patch is evenly distributed closer to the narrow end of the tooth, occupying 2/3 of its length and not extending to the top of the tooth base, as shown in Fig. 139, d.



To adjust the correct position of the drive pinion with the replacement of the ring, it is necessary to disassemble the unit. During assembly, it is necessary to repeat all operations on the preliminary tension of the drive pinion bearings, on checking the torque of resistance to rotation, on the preliminary tension of the differential box bearings and on adjusting the lateral clearance of the main gear pinions.