Lada Niva 4x4, Service Manual

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Gearbox
The design of the gearbox is shown on fig. 3-12, 3-26, 3-34.
Fault diagnosis
Diagnosis Remedy
Noise in gearbox
1. Noise in bearings
2. Worn teeth on gears and syn-
chro units
3. Low oil level in gearbox
4. Axial shaft movement
Difficulty in engaging gears
1. Incomplete clutch release
2. Jammed gearshift lever ball-
joint
3. Deformed gearshift lever
4. Hard movement of fork rods
(burrs, dirty rod sockets, detent
seizure)
5. Hard movement of sleeve on
hub when splines get dirty
6. Deformed gearshift forks
Jumps out of gear or incomplete clutch engagement
1. Worn rod balls and sockets,
weak detent spring
2. Worn synchro unit baulk rings
3. Broken synchro unit spring
4. Worn teeth on synchro unit
sleeve or synchro unit crown
5. Crushed hub short teeth
Oil leak
1. Worn oil seals on input and
output shafts
2. Loose fitting of gearbox cov-
ers, damaged sealings
3. Loose fitting of clutch housing
to transmission casing
Removal and refitting
Removal. Place the vehicle over an inspection pit or on a lift,
put blocks under front wheels and raise the rear axle from one or
two sides. Let off the handbrake and place the gearshift lever in
neutral. Disconnect the wires from the battery.
Take out the front floor mat and the gaiters from the transfer-
and gearbox levers. Remove the aperture covers and sealings.
Unscrew the handles from the transfer box levers.
Push downward lever rod 27 (see fig. 3-12) and with the help
of a screwdriver or any other pointed tool take out the retaining
sleeve 31 from the groove on the lever rod; remove the rod.
Disconnect the brackets that are fixing pipes and mufflers in
the rear part of the vehicle, and then the muffler pipe from the
front exhaust pipe. Disconnect the exhaust pipe clip and remove
the pipe downward.
Undo the lower bolts of the clutch bellhousing cover plate.
Disconnect the "ground" wires from the clutch bellhousing and
the wires from the tail light switch.
Unhook the return spring 1 (fig. 3-13) from the clutch release
fork 5 and take pin 4 out from pushrod 6. Disconnect the slave
cylinder 8 from the clutch bellhousing. Thus, cylinder 8 connect-
ed to the master cylinder hose, remains on the vehicle, what
excludes loosing brake liquid and necessity of the subsequent
bleeding of the clutch release hydraulic drive.
Put clip 2 (A.70025) on the flexible coupling 3 (fig. 3-14) and
tighten. This will help in subsequent removal and refitting of the
flexible coupling. Undo nuts 1 and, by turning the layshaft,
remove the bolts that are fastening the flexible coupling 3 to the
flange of the gearbox output shaft.
Disconnect the speedometer cable from the speedometer
drive unit on the transfer box.
Disconnect the shaft flanges of the front and rear axles drive
from the flanges of the transfer box shafts. Lower and move aside
the axle drive shafts.
Undo the bolts that are fastening the transfer box brackets to
the car body and remove it together with the propeller shaft.
Using a socket spanner 02.7812.9500 undo the bolts fasten-
ing the starter motor to the clutch bellhousing and release it.
Undo the clutch bellhousing cover plate bolts.
Disconnect the engine rear mounting from the crossmember
4 (fig. 3-14), and then remove the crossmember while supporting
the gearbox from below.
Place a jack or other suitable support under the transmission cas-
ing. Using a socket spanner A.55035 undo the fastening bolts and
remove the gearbox together with the clutch bellhousing by moving it
to the rear part of the vehicle so that to take out the gearbox input
shaft from the front bearing and from the clutch disc hub.
ATTENTION. So that not to deform the clutch straps, do
not rest the end of the input shaft on the clutch diaphragm
spring flange when removing or refitting the gearbox.
Refitting the gearbox is a reversal of removal. Before refit-
ting, apply a thin layer of greasing ãëñ-15 (ãàíéã-24) on the
spline end of the input shaft and centralize the clutch disc using
tool A.70081 (see fig. 3-4).
64
1. Renew damaged bearings
2. Replace worn parts
3. Top up oil. Rectify cause of oil
leak
4. Renew bearings or securing
components
1. Replace oil seals
2. Tighten nuts (see torque in
Appendix) or renew seals
3. Tighten nuts
1. See. subsec."Clutch"
2. Clean ball contact surfaces
3. Rectify deformation or renew
lever
4. Repair or renew worn compo-
nents
5. Clean components
6. Straighten forks or renew
1. Renew damaged components
2. Renew baulk ring
3. Renew spring
4. Renew sleeve or gear
5. Renew synchro hub