1997 HONDA CR-V piston ring

Glutch
lllustrated lndex
3RD CLUTCH
lST CLUTCH
SNAP RING
CLUTCH PISTON
RETURN SPRING
NETAINER
RING
CLUTCH PLATESStandard thicknoss:2.00 mm 10.079 inl
CLUTCH DISCSStandard thickne$:1.94 mm (0 0?6 inl
CLUTCH DISCSStandard thicknca3:1.9a mm 10.076 inl
SNAP FING
CLUTCH DRUM
(cont'd)
CHECK VALVE
14-213
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Clutch
lllustrated Index (cont'dl
2ND/4TH CLUTCH
[*
CLUTCH PLATESStendard thickness:2.00 mm {0.079 in)
CLUTCH
OISC SPRING
I
I2ND CLUTCH
CLUTCH PISTON
sPl
I
Repl6ce.
uoavE nr"
CLUTCH PLATESStandard thicknesai2.00 mm {0.079 inl
SNAP RING
14-214
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lST-HOLD CLUTCH
thickness:
RETURN SPRING
c
/
LUTCH PISTON
O.RINGS
14-215
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Glutch
Reassembly
NOTE:
. Clean all parts thoroughly in solvent or carburetorcleaner, and dry them with compressed air.. Blow out all passages.
o Lubricate all parts with ATF before reassembly.
1. Inspect the check valve; if it's loose, replace the pis_ton.
CHECK VALVE
2. Install new O-rings on the clutch piston.
PtsTot{
14-218
3. Install th€ piston in the clutch drum. Apply pressure
and rotate it to ensure proper seating, Lubricate thepiston O-ring with ATF betore insta ing the piston.
NOTE: Oo not pinch the O-ring by installing the pis_ton with too much force.
CLUTCH DRUM
Install the return spring, and spring retainer, thenposition the snap ring on the retainer.
4.
SI{AP RING
SPAI'{G RETAIIIER
REIURN SPRING
CLUTCH DRUM
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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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TOROUE CONTROL OIFFERENTIAL
REAR DIFFERENTIAL ASSEMBLY
OIL PUMP BODY
OIFFERENTIAL CLUTCHHYPOID DRIVEPINION GEAR
OIFFERENTIAL CARRIER
DIFFERENTIAL
HYPOID RING GEAR
DIFFERENTIAI- HOUSING
REAR OII- PUMP
ASSEMBLY
CLUTCH GUIDE
COMPANION FLANG€
CLUTCH HUB
CLUTCH PLATE
HYDRAULIC CONTROL SYSTEM
CLUTCH PISTON
CLUTCH DISC
REAR OIL PUMP
FRONT OIL PUMP
DISC SPRINGFRONT OIL PUMP
DIFFEREMT|AL CLUTCHASSEMBI-Y
THERMAL SWITCHRELIEF VALVEOIL STRAINER
15-5
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Description
Hydraulic Flow
Forward Start and Acceleration l4WD)During a forward start and forward acceleration, the dual pump system can engage four wheel drive.lf the front wheels spin faster than the rear wheels, the front oil pump spins faster than the rear oil pump. The front pump
draws fluid through check valve B and discharges it. Some of the discharged fluid is drawn in the by the rear oil pump.The remaining fluid will pass through check valve E into the clutch piston. There, hydraulic pressure is regulated by twoorifices.
The regulated hydraulic pressure at the clutch piston pushes the plates and discs of the clutch together to form a connec-tion. The engaged clutch then passes driving force from the transfer assembly to the rear wheels, producing 4WD.
oRrFtcEsFRONT OIL PUMPREAR OIL PUMP
Forward Driving at Constant Speed lzWD)When driving forward at a constant speed (cruising), the dual pump system functions in two wheel drive mode.The rotation speed of the front and rear wheels is the same, so the speed of the front and rear pumps is also the same.Fluid discharged by the front oil pump is drawn in by the rear oil pump and is circulated through the system. Becausethere is no pressure built up at the clutch piston, the clutch does not engage, and the vehicle remains in 2WD (front wheeldrive).
FRONT OIL PUMP
15-6
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Forward Deceleration l2WDl
During forward deceleration, the dual pump system functions in two wheel drive mode.
Because of braking characteristics, the speed of the rear wheels may exceed the speed ol the front wheels during deceler-
ation. lf so, the rear oil pump spins faster than the front oil pump.
Fluid discharged by the rear oil pump is simply drawn in again by the rear pump and recirculated. Because there is no
pressure built up at the clutch piston. the clutch piston does not engage, and the vehicle remains in 2WD (front wheel
drive).
Reverse Start and Acceleration (4WD)
During reverse start and reverse acceleration, the dual pump system can engage four wheel drive.
lf the front wheels spin faster than the rear wheels, the front oil pump spins faster than the rear oil pump. The front oil
pump draws in fluid through check valve A and discharges it. {Note that in reverse, the direction of the pumps is the oppo-
site of that during forward driving.)
Some of the fluid that is discharged by the front oil pump is drawn in by the rear oil pump. The remaining fluid passes
through check valve F into the cylinder of the clutch piston, where it is regulated by two orifices.
The regulated hydraulic pressure at the clutch piston may force the plates and discs of the clutch together to form a con-
nectlon. The engaged clutch passes driving force from the transfer assembly to the rear wheels, producing 4WD.
oRtFtcEsFRONT OIL PUMP
{cont'd)
15-7
REAR OIL PUMP
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