SANY SRT95C Off-Highway Truck. Service Manual

3 REAR AXLE ASSEMBLY

AND INSTALLATION

Overview of operating principle

See Fig.3-1 for the numbers in the brackets.
The  rear  axle  assembly  and  installation
consist of the rear axle assembly (1) and rear
axle mounting part (2). The rear axle assembly
also connects the rear wheels to the chassis
through A-frame,  Link,  and  the  rear  ride
cylinders. The rear axle assembly is centrally
mounted on the rear frame crossmember with
a tapered pin  and component parts, which
allows the axle to oscillate as the truck moves
over uneven terrain.

Removal

See Fig.3-1 for the numbers in the brackets.
1. Position the vehicle in a level work area,
apply the parking brake and switch off the
engine.

Fig.3-1 Rear axle assembly and installation

1. Rear axle assembly

2. Rear axle mounting part

Rear Axle Assembly And Installation

2. Turn the steering wheel in both directions
several  times  to  relieve  pressure  in  the
steering system. Operate the treadle valve
continuously to relieve pressure in the braking
system. Block all road wheels.
3. Disconnect brake, cooling, breather and
lubrication lines. Drain all the lubricant from
the  axle,  brake  assemblies  and  planetary
assemblies  into  suitable  containers.  See
Section  3.1.3  ‘MAIN  REDUCER  AND
DIFFERENTIAL ASSEMBLY’ and Section 3.1.5
‘REAR BRAKE AND INSTALLATION’, cap all

open lines and fittings to prevent entry of dirt.

Note

: Avoid spilling lubricant on tyres, as it will

deteriorate the rubber.
4. Jack up or lift up the truck so that its weight
is not supported by the tyres any more.
Securely support the truck at this position.

5. Remove four bolts from the driveline flange

and  swing-driveline  away  from  the  main
reducer and differential assembly. Punch mark
both  flanges  to  facilitate  installation.  (See
chapter 19 ‘Installation of Transmission Shaft’.
6.  If  necessary,  remove  the  tyre  and  rim
assembly according to the method in Chapter
4 ‘REAR WHEEL ASSEMBLY’.

warning

To prevent personal injury and property

damage, be sure lifting equipment is of

adequate capacity and properly secured to

do the job safely.

7. Position a hydraulic jack under the axle at
the differential housing, being sure jack is of
suitable capacity and proportions to lift and
balance the axle assembly. Place wheeled
dollies at both ends of the axle for wheels to
rest on when the axle is lowered. Raise axle
just enough to take weight off centre tapered
pin.
8. Remove lower ends of rear ride cylinders.

Rear Axle Assembly And Installation

Refer to Section 22, Rear suspension cylinder.
9.  Dismantle  the  bolt,  elastic  washer,  flat
washer and articulated shaft used for installing
Link on the frame, and remove the spacer
ring.
10.  Remove  the  bolts  and  other  parts  for
connecting A-frame to the rear axle mounting
part on the frame assembly.
11. Drive tapered pin  out of the chassis using
a soft drift. As tapered pin moves out, remove
spacers. Lower the axle assembly onto the
wheeled dollies and roll out from beneath the
vehicle.
12. Use the hoist device to lift the rear axle
assembly  and  place  it  onto  the  rear  axle

assembly fixture.

Inspection

1. Clean all metal parts in a suitable solvent,
using a brush to clean bearings. Dry all parts
on a clean surface and allow bearings to dry
naturally. Make sure parts are free from dirt.
2. Check all inner and outer grooves for
cleanliness. Check components for cracks,

scores, blemishes or burrs. Use a fine stone to

smooth out defective areas. Replace any parts
that show excessive wear.
3. Inspect fittings, plugs, studs and their
seating positions for thread wear. If threads
in any of these parts are damaged, replace
parts.
4. Check bushings, bearings and snap
rings for wear or warped condition. Replace
defective parts.
5. Replace the used washer and damaged
O-ring.

Rear Axle Assembly And Installation

warning

To prevent personal injury and property

damage, be sure lifting equipment is of

adequate capacity and properly secured to

do the job safely.

Assembly

See Fig.3-1 for the numbers in the brackets.

Note

: Tighten all fasteners without special

torques specified to standard torques listed
in Section38.2 Standard bolt and nut torque

specifications. Tighten the connecting joint of

hydraulic pipeline and replace all 'O'rings.
1. After the rear axle assembly is completely
reassembled, use a proper hoist device to lift it
up and place it under the truck and align under
the chassis.
2. Using a hydraulic jack of suitable capacity
and proportions to lift and balance the axle
assembly, raise the axle assembly into position
in the chassis. Insert spacers and, using a soft
drift, drive in tapered pin.
3. Install rear ride cylinders to the chassis and
axle assembly as outlined in Section 22 'Rear
suspension cylinder'.
4. With the axle group securely fastened to
the rear ride cylinders and the two sections of
the chassis at Link and A-frame, release and
remove thehydraulic jack.
5. Align the punch marks, as marked during
removal,  on  the  driveline  and  differential
flanges, and secure with four bolts. Refer to
Chapter 19 ‘Installation of Transmission Shaft’.
6. If removed, replace tyre and rim assemblies
as  outlined  in  Section  4'REAR  WHEEL
ASSEMBLY'.
7.  Remove  blanking  caps  and  reconnect
all brake, cooling, breather and lubrication
lines.  Refer  to  Section  3.1.5  'rear  brake
assembly'  and Section 3.1.3,'Main reduxer
and differential.
8. According  to  the  contents  specified

Rear Axle Assembly And Installation

i n S e c t i o n 3 6 . 1 ‘ L U B R I C AT I O N A N D
MAINTENANCE’, add lubricating oil into the
rear axle housing, planetary assembly and
rear brake assembly.
9. Lubricate the rear axle assembly through

lube fittings with lubricant specified in Section

36.1'LUBRICATION AND MAINTENANCE' .
10. Refer to Section 3.1.5 ‘REAR BRAKE
AND INSTALLATION’ for exhaust of the brake
system.

warning

To prevent personal injury and property

damage, be sure lifting equipment is of

adequate capacity and properly secured to

do the job safely.

Maintenance

Correct lubrication is critical to routine
maintenance of planetary and axle shaft and
main reducer and differential assembly. Refer
to the lubrication interval and proper lubricant

specified in Section 36.1 ‘LUBRICATION AND

MAINTENANCE’.

Axle diagnosis

Noises originating in the tyres, transmission or
driveline might be attributed by mistake to
the axle. Therefore, all possible sources of
noise should be investigated before deciding
the axle is at fault. true axle noises may be
located by lifting or jacking the truck until all

driving wheels are clear of the floor or ground.

Securely block the truck in this position. Run
power train at moderate speed. Be certain
all tyres are off the ground and, to prevent
damage to the differential, see that neither
rear brake drags.

Rear Axle Assembly And Installation

3.1 Rear Axle Assembly

Overview of operating principle

See Fig.3-2 for the numbers in the brackets.
The rear axle assembly consists of the
planetary assembly and rear half shaft (1),
rear hub assembly (2), rear brake assembly
(3), rear axle housing assembly (4) and main
reducer and differential assembly (5). The
rear axle also connects the rear wheels to the
chassis through A-frame, link and the rear ride
cylinders. The rear axle assembly is centrally
mounted on the rear frame crossmember with
a tapered pin and component parts, which
allows the axle to oscillate as the truck moves
over uneven terrain.

Fig.3-2 Rear axle assembly

1. planetary assembly and axle shaft

4. Rear axle housing assembly

2. Rear hub assembly

5. Main reducer and differential assembly

3. Rear brake assembly

Rear Axle Assembly And Installation

Disassembly

See Fig.3-2 for the numbers in the brackets.
1. Position the vehicle in a level work area,
apply the parking brake and switch off the
engine.
2. Turn the steering wheel in both directions
several times to relieve pressure in the
steering system. Operate the treadle valve
continuously to relieve pressure in the braking
system. Block all road wheels.
3. Disconnect brake, cooling, breather and
lubrication lines. Drain all the lubricant from
the axle, brake assemblies and planetary
assemblies into suitable containers.
See Section 3.1.3 ‘Main reducing device and
differential assembly’ and Section 3.1.5 ‘REAR
BRAKE AND INSTALLATION’, Cap all open

lines and fittings to prevent entry of dirt.

Note

: Avoid spilling lubricant on tyres, as it will

deteriorate the rubber.
4. Jack up or lift up the truck so that its weight
is not supported by the tyres any more.
Securely support the truck at this position.

warning

To prevent personal injury and property

damage, be sure lifting equipment is of

adequate capacity and properly secured to

do the job safely.

5. Remove four bolts from the driveline flange

and swing-driveline away from the differential.
Punch mark both flanges to facilitate
installation. (See chapter 19 ‘Installation of
Transmission Shaft’. )
6. If necessary, remove the tyre and rim
assembly according to the method in Chapter
4 ‘REAR WHEEL ASSEMBLY’.
7. Position a hydraulic jack under the axle at
the differential housing, being sure jack is of
suitable capacity and proportions to lift and
balance the axle assembly. Place wheeled

Rear Axle Assembly And Installation

dollies at both ends of the axle for wheels to
rest on when the axle is lowered. Raise axle
just enough to take weight off centre tapered
pin.
8. Remove lower ends of rear ride cylinders.
Refer to Section 22, Rear suspension cylinder.
9.  Dismantle  the  bolt,  elastic  washer,  flat
washer and articulated shaft used for installing
link on the frame, and remove the spacer ring.
10.  Remove  nut,  pin  and  washer  used  for
connecting A-frame to the frame assembly,
and remove the split bush from the tapered
pin.
11. Drive tapered pin  out of the chassis using
a soft drift. As tapered pin moves out, remove
spacers. Lower the axle assembly onto the
wheeled dollies and roll out from beneath the
vehicle.
12.  Use  a  hoist  device  to  lift  up  the  rear
axle assembly and place it on the rear axle

assembly placement fixture.

warning

To prevent personal injury and property

damage, be sure lifting equipment is of

adequate capacity and properly secured to

do the job safely.

Disassembly

See Fig.3-2 for the numbers in the brackets.
1. If the gear oil is not discharged, remove the
oil filling screw cover and the oil discharge
screw cover from the rear axle and the
planetary gear carrier first. Drain the gear oil
inside the rear axle assembly into a clean and
proper container.
2. Remove the thrust cover in the planetary
assembly and axle shaft (1), take down the
retainer ring, sun gear and axle shaft.
3. Remove the nut connecting the planetary
assembly and rear hub assembly (2). Then
remove the planetary assembly and discard
the O-ring installed on planetary gear carrier.

Rear Axle Assembly And Installation

At the same time, use a proper hoist device
to lift the planetary assembly and place it on a
clean work bench.
4. Remove the rear hub assembly (2), use
a  proper  hoist  device  to  lift  up  the  rear
hub  assembly  (2)  and  place  it  on  a  clean
workbench.
5.  Remove  the  nut  connecting  rear  hub
assembly (2) and rear axle housing assembly
(4), then use a proper hoist device to lift the
rear brake assembly (3). Then remove the rear
brake assembly (3) and place it on a clean
workbench and discard the damaged O-ring.
6. Remove the nut for connecting the main
reducer and differential assembly (5) and the
rear axle housing assembly (4). At the same
time, use the proper hoist device to lift up the
main reducer and differential assembly (5) and
place it on a clean workbench.
7. If necessary, the A-frame can be dismantled.

warning

To prevent personal injury and property

damage, be sure lifting equipment is of

adequate capacity and properly secured to

do the job safely.

Inspection

scores, blemishes or burrs. Use a fine stone to

smooth out defective areas. Replace any parts
that show excessive wear.
3. Inspect fittings, plugs, studs and their
seating positions for thread wear. If threads
in any of these parts are damaged, replace
parts.
4. Check the bush, bearing and snap ring for
wearing or deformation. Replace the defective

Rear Axle Assembly And Installation

parts and components.
5. Replace the used washer and the damaged
O-ring.

Assembly

See Fig.3-2 for the numbers in brackets.

Note

: Tighten all fasteners without special

torques specified to standard torques listed
in Section38.2 Standard bolt and nut torque

specifications.
1. If the oil filling screw cover and oil drainage

screw cover are removed, then they should be
installed onto the axle housing.
2. Install the main reducer and differential
assembly (5) onto the axle housing. Use the

nut to fix and tighten it to the tightening torque
of 541N•m. Refer to Section 3.1.3 ‘MAIN

REDUCER AND DIFFERENTIAL ASSEMBLY’.
If the A-frame is removed, then install it onto the
axle housing. To assemble the main reducer
and differential assembly and A-frame, select
and use a proper hoist device to lift them up.
3. Install the rear brake assembly (3) onto the
rear axle housing assembly (4). In addition,
use the nut to fix it and tighten it to the

tightening torque of 1166N•m - 1193N•m. To

assemble the rear brake assembly, select and
use a proper hoist device to lift them up.
4. Use a proper hoist device to lift up the rear
hub assembly (2), and install it onto the rear
axle housing assembly (4).
5. Use a proper hoist device to lift up the
planetary assembly and install it onto the rear
hub assembly (2). Use the nut to fix it and

tighten it. The tightening torque is 650N•m.

6. Install the axle shaft into the rear axle
housing assembly (4) and insert the external
spline without circlip groove at its end into
the internal spline of differential axle shaft
bevel gear in the main reducer and differential
assembly (5). Then install the sun gear and

the retainer ring; finally install the thrust cover

and tighten up the bolts according to the

specified moment.

Rear Axle Assembly And Installation

warning

To prevent personal injury and property

damage, be sure lifting equipment is of

adequate capacity and properly secured to

do the job safely.

Installation

See Fig.3-2 for the numbers in the brackets.

Note

: Tighten all fasteners without special

torques specified to standard torques listed
in Section38.2 Standard bolt and nut torque

specifications. Tighten the connecting joint of

hydraulic pipeline and replace all 'O'rings.
1. After the rear axle assembly is completely
reassembled, use a proper hoist device to lift
it up and place it under the truck. Then align it
with the frame.
2. Using a hydraulic jack of suitable capacity
and proportions to lift and balance the axle
assembly, raise the axle assembly into position
in the chassis. Insert spacers and, using a soft
drift, drive in tapered pin.
3. Install the rear suspension cylinder onto
the frame and rear axle assembly. Refer to
Chapter 22 ‘REAR SUSPENSION SYSTEM’.
4. With the axle group securely fastened to
the rear ride cylinders and the two sections of
the chassis at  Link  and A-frame, release and
remove thehydraulic jack.
5. Align the punch marks, as marked during
removal,  on  the  driveline  and  differential
flanges, and secure with four bolts. Refer to
Chapter 19 ‘Installation of Transmission Shaft’.
6. If removed, replace tyre and rim assemblies
as  outlined  in  Section  4'REAR  WHEEL
ASSEMBLY'.
7. Remove blanking caps and reconnect all
brake, cooling, breather and lubrication lines.
Refer to Section 3.1.5 'REAR BRAKE AND
INSTALLATION'    and  Section  3.1.3,'MAIN
REDUCER AND DIFFERENTIAL ASSEMBLY'.
8. According  to  the  contents  specified

Rear Axle Assembly And Installation

lube fittings with lubricant specified in Section

36.1'LUBRICATION AND MAINTENANCE' .
10. See Section 3.1.5 ‘REAR BRAKE AND
INSTALLATION’ for exhaust of the brake
system.

warning

To prevent personal injury and property

damage, be sure lifting equipment is of

adequate capacity and properly secured to

do the job safely.

Maintenance

Correct  lubrication  is  critical  to  routine
maintenance  of  planetary  assembly  and
axle shaft and main reducer and differential
assembly.  Refer  to  the  lubrication  interval

and proper lubricant specified in Section 36.1

‘LUBRICATION AND MAINTENANCE’.

Axle diagnosis

driving wheels are clear of the floor or ground.

Securely block the truck in this position. Run
power train at moderate speed. Be certain
all tyres are off the ground and, to prevent
damage to the differential, see that neither
rear brake drags.

Rear Axle Assembly And Installation

Fault diagnosis system

Faults

Cause

Elimination

Noise

Lubrication is insufficient or incorrect.

C h e c k o i l l e v e l a n d a d d t h e
lubricating oil of the right type.

Wheel bearing is scratched or roughened.

Replace the bearing.

Gear teeth in planetary chipped

Replace the gear.

Loss of lubri-
cating oil

Oil level of lubricating oil is too high.

Drain exce-ssive oil.

Lubricating oil contains too many foams.

Add correct lubricating oil.

Oil seal is worn or damaged.

Replace the oil seal.

Breather is clogged.

Clean the breather.

Nut or bolt is loose.

Tighten the nut or bolt.

Increase of
lubricating oil

The differential housing brea-ther is clogged. Clean the breather.

High temp-
e r a t u r e o f
p l a n e t a r y
mechanism

Lubricating oil is insufficient or incorrect.

Check oil level and repl-ace it with
the lubricating oil of the right type.

Pinion bearings seized

Replace the bearing.

Rear Axle Assembly And Installation

Fig.1 Sectional View of Two Stage Planetary Assembly

3.1.1 Two stage planetary assembly and

axle half

1. Hardened washer

16. Roller spacer

31. Sun gear retainer

2. Washer

17. Planetary carrier

32. Sun gear

3. Roller

18. Thrust plate

33. Lockwire

4. Roller

19. Thrust spacer

34. Cover

5. O-ring

20. Roller spacer

35. Planetary pinion

6. cover

21. Pin retainer

36. O-ring

7. Bolt

22. Planetary pinion

37. Primary planetary gear shaft

Rear Axle Assembly And Installation

8. Bolt

23. Pinion pin

38. Ring gear

9. Bolt

24. Thrust washer

39. Carrier cover

10. Bolt

25. Ring gear carrier

40. Pin retainer

11. Screw

26. Ring gear retainer

41. Axle half

12. Bolt

27. Ring gear

42. Snap ring

13. Sun gear

28. Planetary carrier

43. Screw

14. Thrust plate

29. O-ring

15. Thrust spacer

30. Thrust washer

Plenetary assembly and axle shaft

Description and operation

Numbers in parentheses refer to Fig.1.
The planetary gearing shown is a two -stage
planetary gear assembly. This assembly
contains two sun gears(13&32), two planetary
carriers (17&28) with planet pinions (22&35)
and two ring gears (27&38), to provide
compound gear ratio to the drive wheels. Axle
shaft (41) is driven by the differential and turns
the first sun gear (13) to which it is splined.
The sun gear (13) meshes with and rotates

the first stage planetary pinions (35)which turn

first stage planetary carrier(17) . First stage
planetary carrier(17)meshes with secondstage
sun gear(32) and planet pinions (22) mesh

with ring gear (27). The interaction of the first

stage sun gear (13), planet pinions (35) and
ring gear (38) causes first stage planetary
carrier (17) to rotate which, in turn, drives the
second stage sun gear (32). Second stage
sun gear (32) meshes with and rotates second
stage planetary pinions (22) which, in turn, are
meshed with ring gear (38). Since second
stage ring gear (38) is splined to the wheel
spindle it can not turn and forces the second
stage planetary carrier (28) to rotate. Hence,
two sets of planetary pinions (22&35) with
two different gear ratios interact with their
respective meshed parts resulting in planetary
carrier(28) being the output to the drive
wheels. These combined planetary sets,
therefore, provide a compound gear ratio to

Rear Axle Assembly And Installation

multiply the torque applied to the drive wheel
by the axle shaft (41).

Planetary Gearing-Towing

Numbers in parentheses refer to Fig.1

warning

Be sure adequate steering and braking

pressure are available before towing to

prevent injury or damage enroute.

If the truck is to be towed, as in the case of a
breakdown, the axle shaft (41) and sun gear
(13)should be removed from the planetary
assemblies. The removal will prevent possible
damage to the power train components during
towing. The axle shaft(41) and  sun gear(13)
can be removed easily by taking off the cover
(34)  and simply sliding the axlf shaft(41),
together  with  sun  gear(13),  out  of  each
planetary assembly by hand. Be certain the
driving  cover (34) are installed to protect the
planetary assemblies from road dust and dirt
while towing is in progress.

Removal and Disassembly

Numbers in parentheses refer to Fig.2.

Note

: The planetary assembly can be

removed from the wheel without removing the
tyre and rim assembly.

warning

To prevent personal injury and property

damage, be sure lifting equipment is of

adequate capacity and properly secured to

do the job safely.

1. Position the vehicle in a level work area with
plug (6) at its lowest point. Apply the parking
brake and switch off the engine.

Rear Axle Assembly And Installation

SANY SRT95C Off-Highway Truck. Service Manual - page 7