We disassemble the gearbox for repair and replacement of parts
We remove the front axle, as indicated in the previous article.
Removing the steering knuckles
Using keys for 14 and 17, we unscrew two bolts and six nuts securing parts of the gearbox housing
We take out the bolts and disconnect the parts of the crankcase
We remove the cardboard gasket and take out the box of satellites with the driven gear
Removing the drive gear
We unscrew the six bolts securing the drive gear bearing cover with a 14 key
Removing the bearing cover
When assembling, it is necessary to ensure that the oil drain channel in the cover, crankcase and gaskets matches.
Remove gasket and ring
By striking with a hammer through a soft metal drift on the end of the drive gear shaft, we press it out
We pull the outer ring and the rear inner ring of the double roller bearing off the shaft with a puller
Remove rear inner race and bearing outer race
We mark the bearing rings in order to install them in their original places during assembly
Remove shims and spacer
Tighten the inner ring of the bearing with a puller
If a puller is not available, the bearings can be knocked down with a hammer by striking the inner ring through a drift
We tighten with a puller and remove the roller bearing
The outer rings of the satellite box bearings can be pressed out with a special puller or use an inertial puller with a hook at the end
With a puller, we press the inner rings of bearings with rollers from the satellite boxи
Remove rings and shims
We fold the bearings complete with rings and shims in order to install the parts in their original places during assembly
With a center punch we mark the relative position of the driven gear and the satellite box
We clamp the box of satellites in a vise and with a head of 19 we unscrew ten bolts securing the driven gear
We remove the driven gear, if necessary, striking through a soft drift with a hammer
We unscrew the head for 14 eight bolts connecting the parts of the box
We disconnect the satellite box and remove the thrust washer of the side gear
Removing the side gear
Remove the axle with two satellites and the satellites from the axle
We take out the other axis of the satellites and remove them
We take out the side gear and its thrust washer
Before assembly, we wash all parts in kerosene or diesel fuel and inspect them
Any cracks are unacceptable on the parts. The gear teeth must be free of scuffs, chipping and heavy wear.
The bearings should rotate easily without clicking or binding. On rollers and rings, chipping, chips and heavy wear are unacceptable
Bearing cages should not have gaps and deformations.
We replace damaged and worn parts. After a run of more than 100 thousand km, we recommend replacing the bearings, regardless of their condition.
We assemble the main gear in the reverse order of disassembly, lubricating the bearings and gears with gear oil.
Bearings can be pressed with hammer blows through suitable sizes:
- tool head or pipe section;
- tubular wrench
We press the outer rings of the bearings of the satellite box into the crankcase with hammer blows in a circle through a soft metal drift
Before assembly, degrease the fastening bolts of the parts of the satellite box, the fastening bolts of the driven gear, as well as their threaded holes with a solvent or acetone and apply an anaerobic sealant to the thread
We pay special attention to the cleanliness of the end seating surfaces of the driven gear and the satellite box. The slightest dirt or nicks on them are unacceptable
We remove the existing damage with an abrasive tool, followed by a thorough washing of the parts in kerosene or diesel fuel
Adjustment of bearings and gears of the final drive
Adjustment is made only when replacing gears (completely), bearings, as well as when noise appears during the operation of the final drive
The drive gear bearing is adjustable by selecting the thickness of the gasket package between its inner rings. To do this, we assemble the drive gear assembly with clean bearings lubricated with gear oil. At the same time, we do not install the cuff in the cover
We tighten the shank nut with a torque of 17–21 kgf.m. After that, the gear should turn by hand without much effort, and there should be no axial play.
If there is axial play, remove one of the shims. If the rotation is too tight, add one gasket
We finally check the adjustment with a dynamometer by hooking it on the flange hole
The force when turning the gear should be in the range of 1.5–3.0 kgf for worn-in and 2.0–3.5 kgf for new bearings
The bearings of the satellite box are adjustable in the following order:
- we press the inner rings with rollers onto the necks of the box so that there is a gap of 3.0–3.5 mm between the bearing ring and the end of the box. Bearings must be clean and lubricated with oil.
We install the satellite box in the main gear housing, put the gasket in the housing connector and evenly tighten the bolts and nuts of the housing, connecting its parts. At the same time, we rotate the drive gear to properly install the rollers in the bearings.
Finally tighten the crankcase bolts and nuts
We unscrew the bolts and nuts, carefully disconnect the crankcase and take out the box of satellites.
We measure the gaps between each bearing and the end of the box with a feeler gauge.
We select a package of gaskets, the thickness of which is equal to the total clearance of both bearings and add another gasket 0.1 mm thick to create a preload
We remove the inner rings of the bearings, divide the selected package of gaskets in half and, having installed the gaskets in their places, press the inner rings of the bearings to the stop.
After that, we adjust the side clearance in the meshing of the gears, for which:
install the satellite box, connect the halves of the crankcase, tighten the bolts and nuts
We measure the backlash in engagement with the indicator, shaking the drive gear in both directions
At a radius of 40 mm at the drive gear flange (bolt centers), the indicator readings should be in the range of 0.35–0.77 mm.
To increase the gap, remove the gaskets from under the bearing of the satellite box from the side of the driven gear and rearrange them under another bearing. To reduce the gap, do the opposite
We assemble the gearbox, install the cuff, during assembly we apply sealant to the gasket and thread of the bolts
We finally check the operation of the gearbox by rotating the drive gear flange. There should be no sticking in the engagement, the rotation should be smooth, without clicks and play