gears HONDA CR-V 1997 RD1-RD3 / 1.G Owner's Guide

Description
Rear Differential
Outline
The Real-time 4WD-Dual Pump System model has a hydraulic clutch and a differential mechanism in the rear differential
assembly. Under normal conditions, the vehicle is driven by the front wheels. However, depending on to the driving force
of the front wheels and the road conditions. the system instantly transmits appropriate driving force to the rear wheels
without requiring the driver to switch between 2WD (tront wheel drive) and 4WD (four wheel drive). The switching mecha-
nism between 2WD and 4WD is integrated into the rear differential assembly to make the system light and compact.
ln addition, the dual-pump system switches off the rear-wheel-drive force when braking in a forward gear. This allows the
braking system to work properly on models equipped with an Anti-lock Braking System (ABS).
Construction
The rear differential assembly consists of the torque control differential case assembly and the rear differential carrier
assembly. The torque control differential case assembly consists of the differential clutch assembly, the companion
flange, and the oil pump body assembly. The rear differential carrier assembly consists of the differential mechanism. The
differential drive and driven gears are hypoid gears.
The oil pump body assembly consists of the front oil pump, the rear oil pump, the hydraulic control mechanism, and the
clutch piston. The clutch piston has a disc spring that constantly provides the differential clutch assembly with a preset
torque to Drevent abnormal sound.
The clutch guide in the differential clutch assembly is connected to the propeller shaft via the companion flange, and it
receives the driving force lrom the transfer assembly. The clutch guide rotates the clutch plate and the front oil pump in
the oil pump body.
The clutch hub in the differential clutch assembly has a clutch disc that is splined with the hypoid drive pinion gear. The
hypoid drive gear drives the rear oil pump.
The front and rear oil pumps are trochoidal pumps. The rear oil pump capacity is 2.5 percent larger that the front oil pump
to handle the rotation difference between the front and rear wheels caused by worn front tires and tight corner braking.
The oil pumps are designed so the fluid intake works as a fluid discharge when the oil pumps rotate in reverse. Genuine
Honda CVT fluid is used instead of differential fluid.
Operation
When there is a difference in rotation speed between the front wheels (clutch guide) and rear wheels (hypoid driven gear),
hydraulic pressure from the front and rear oil pumps engages the differential clutch, and drive force from the transler
assembly is applied to the rear wheels.
The hydraulic pressure control mechanism in the oil pump body selects 4WD mode when the vehicle is started abruptly,
or when accelerating in a forward or reverse gear (causing rotation difference between the front and rear wheels). or
when braking in reverse gear {when decelerating). lt switches to 2WD mode when the vehicle is driven at a constant speed
in forwar! or reverse gear (when there is no rotation difference between the front and rear wheels), or when braking in a
fo rwa rd gear (when decelerating).
To protect the system, the differential clutch assembly is lubricated by hydraulic pressure generated by the oil pumps in
both 4WD and 2WD modes. Also, the thermal switch relieves the hydraulic pressure on the clutch piston and cancels 4WD
mode if the temDerature of the differential fluid rises above normal.
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Troubleshooting (Manual Transmissionl
When starting and accelerating in forward gears (4WD
mode)
1. Lift up the vehicle so all four wheels are off the
ground {see section 1)
3.
Start the engine, and let it run until it warms up (the
radiator fan comes on at least twlce).
With the engine at idle, shift into 1st gear and
release the clutch.
Apply the parking brake firmlY
. lf the engine stalls, the 4WD system is normal.
. lf the engine continues running, there is a prob-
lem in 4WD system. Check the differential fluid. lf
the differential fluid is normal, replace the torque
control ditferential case kit.
2.
When starting and accelerating in reverse gear (4WD
model
1. Lift up the vehicle so all four wheels are off the
ground (see section 1).
Start the engine, and let it run until it warms up (the
radiator fan comes on at least twice)
With the engine at idle, shift into reverse gear and
release the clutch.
Apply the parking brake firmlY
. lf the engine stalls, the 4WD system is normal.
. lf the engine continues running, there is a prob-
lem in 4WD system. Check the differential fluid lf
the differential fluid is normal, replace the torque
control differential case kit.
3.
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Rear Differential AssemblY
Troubleshooting
Most problems in the unit are to be diagnosed by identifying noises from the gears or bear'ngs'
care should be taken during diagnosis not to confuse differential noises with those from other drivetra'n components'
SymptomProbable CauseRemedy
Will not go into 4WD mode. Fluid level too low
. Incorrect fluid type
. Add fluid. Replace
Will not return to 2WD modeIncorrect fluid typeDrain and fill the differential
Gear or bearing noisesFluid level too low
Incorrect fluid type
Damaged or chipped gears
Add fluid
Drain and fill the differential
Replace the differential carrier
assemory
Overheating. Fluid leveltoo low
. Incorrect fluid type
. Add fluid. Drain and fill the differential
Fluid leakFluid level too high
Clogged breather hose
Worn or damaged oil seal
Damaged sealing washer
Loose mounting bolts or inade-
quate sealing
Lower to proper level
Clean or replace
Replace
Replace
Recheck torque or aPPIY sealant
15-13
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50. Install the valve body unit on the gearbox. and
tighten the flange bolts to the specified torque.
VALVE BODYFLANGE BOLT20 N.m 12.0 kgt.m, 14lbtft)
ct.
SHIM SET(four shims)
Measure the clearance between the gearbox and
valve body unit using a feeler gauge. Measure the
clearance at the poinl midway between the two
mounting bolts.
GAUGE
Determine the required thickness of the 32 mm
shims by subtracting the clearance obtained in the
step "c" from the total thickness of the four shims.
(Total thickness of the 4 shims) - (Clearance) =
Reouired thickness of the shims
Select the shims so that the total thickness is close
to, but less than, the required thickness.
Example:
Measurement is 0.28 mm (0.011 in);
0.70-0.28=0.42 mm (0.028-0.011 = 0.017 in)
The selected shims should be 0,25 mm (0.010 inl and
0.15 mm (0.006 in) in thickness.
lf the required shim thickness is 0.10 mm or less, no
shrms are necessary.
53. Set the selected 32 mm shims on the bearing sur-
face of the gearbox housing.
VALVE BODY UNITla lbl.frl
Coat the new O-ring with grease, and carefully fit it
on the valve housing.
Apply grease to the needle bearing in the gearbox
housing.
Install the valve body unit on the gearbox housing
by engaging the gears. Note the valve body unit
installation position (direction of line connection).
Tighten the flange bolts to the specified torque.
(cont'd)
FLANGE BOLT20 N.m (2.0 kgf.m,
/a)E?
E
O.RINGReplace.
-6{
NEEDLE BEARING
-6lr
54.
56.
57.
17-47
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