Page 796 of 1395

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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Page 797 of 1395

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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Page 798 of 1395

Description
Hydraulic Flow (cont'dl
Reverse Driving at Constant Speed l2WD)when driving in reverse at a constant speed, 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. But, becausethe there is a difference in the capacity between the two pumps, fluid flows through check valve E, and then through ori-Iices. This fluid lubricates and cools the clutch assembly and bearings.ls this condition, only a low pressure is built up at the clutch piston. Therefore the clutch does not engage, and the vehicleremains in 2WD (front wheel drive).
Reverse Deceleration l/tWDl
During reverse deceleration, the dual pump system can engage four wheel drive.When decelerating in reverse direction, the speed of the rear wheels may exceed the speed of the front wheels (due toengine braking). In this condition, the rear oil pump draws fluid through check valves B and C. Fluid discharged from therear oil pump then flows through check valve E to the clutch piston. There, pressure 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,nection. The engaged clutch passes driving force from the transfer assembly to the rear wheels, producing 4WD.
oRtFtcEsREAR OIL PUMP
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Page 805 of 1395
Rear Differential Assembly
lllustrated Index
O.RINGReplace.
6xl.0m12 N.m (1.2 kgf m,8.7 lbt'ftl
BACK-UP RING
COMPANION FLANGE
CLUTCH HUB/PLATES/DISCS
DIFFERENNAL CLUTCHASSEMBLY
DOWEL PINS
OIL PUMP DRIVESHAFT
LOCKNUT, 24 mmReplace.118 N.m (12.0 kgtm.87 rbt ft)
OIL SEALReplace.
PRESSURE PLATE
THBUST NEEDLEAEARING""t",at\(
'd'
CLUTCH GUIDE
OIL PUMPPIN
e
MAGNET
6x1.0mm12 N.m 11.2 kgt'm,8.7 lbf'ft|
OIL STRAINER
15-15
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Page 812 of 1395
Rear Differential Assembly
Disassembly (cont'dl
9. Remove the shim and the clutch quide.
d"HIM'30mm
CLUTCH GUIDE
Remove the clutch hub/plates/discs and the pressure
prare.
10.
CLUTCH HUB/PLATES/OISCS
k
ffi-:*
_zz PRESSURE PLArE
@-
15-22
11. Remove the thrust needle bearing and the oil pump
driveshaft.
Remove the oil pump body assembly, the oil pump
pin, the magnet, and the oil strainer.
OIL PUMP BODY ASSEMBLY
MAGNET
OIL PUMP PIN
12.
OIL STRAINERInspect for damageor clogging.
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Page 814 of 1395

Rear Differential Assembly
Reassembly (cont'dl
7. Install the clutch hub/plates/discs, then align the pro-
jection of the plates with the discs.
M, 30 mm
CLUTCH GUIDE
sHl
,/
.A-\,/r\-7
8.
9.
CLUTCH HUA/PLATES/Dtscs
Installthe clutch guide and the 30 mm shim.
Apply liquid gasket to the sealing surface of the
torque control differential case, and note these
rlems:
. Use liquid gasket (P/N 08718 - 0001).
. Remove any dirt or fluid from the sealing sur-
face.
. lf 20 minutes have passed after applying liquid
gasket, reapply it before you assemble the hous-
ings. Allow it to cure at least 30 minutes after
assembly before filling differential with fluid.
TOBOUE CONTROLDIFFERENNAL
--- Apply liquid gaskot
15-24
6x1.0mm12 N.m 11.2 tgf m,8.7lbt.ftl
10. lnstall the dowel pins and toroue control differential
case.
TOROUE CONTNOL
11. Install the companion flange, O-ring, back-up ring,
disc spring washer, and the locknut.
NOTE: Apply CW fluid to the O-ring.
,24mm
DISC SPRING WASHER,2a mm
lnstall in this direction.
@+-_alcr-upnwc
COMPANION FLAI{GE
/r-
K@#/
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Page 1155 of 1395

Clutch Inspection
Check the plated parts of the armature plate for color
changes, peeling or other damage. lf there is dam-
age, replace the clutch set.
Check the rotor pulley bearing play and drag by rotat-
ing the rotor pulley by hand. Replace the clutch set
with a new one if it is noisy or has excessive play/drag.
Measure the clearance between the rotor pulley and
the armature plate all the way around. lf the clear-
ance is not within specified limits, the armature plate
must be removed and shims added or removed as
required, following the procedure on page 22-66.
Cloarance: 0.5 t 0.15 mm {0.020 t 0.q)6 in)
NOTE: The shims are available in four thicknesses:
0.1 mm. 0.2 mm. 0.4 mm and 0.5 mm
ABMATUBE
ROTOR
. Release the field coil connector from the holder, then
disconnect it. Check the thermal protector for conti-
nuity, lf there is no continuity, replace the thermal
prorecror.
NOTE: The thermal protector will have no continuity
above 251.6 to 262.4"F 1122 to 128"C). When the tem-perature drops below 240.8 to 219.8"F (116 to 104'C),
the thermal protector will have continuity.
Check resistance of the field coil.
Field Coil Resistance: 3.2 i 0.15 ohms at 68"F {20'C)
lf resistance is not within specifications, replace the
field coil.
22-65
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Page 1156 of 1395
Compressor
Glutch Overhaul
1. Remove the center nut while holding the armature
plate with the tool.
A,/C CLUTCH HOLOERlCommerciallY .vailable)Robinair: P/N 1020,0Ked-Mooro: P/N J37872
CENTER NUT17.6 N.m ('1.8 kgf.m, 13lbfft)Reolace. \
i
2. Remove the armature plate by pulling it up by hand.
ARMATURE PLATE
sHtMls)Replace.
za:s
(i@,
22-66
3. Remove the snap ring B with snap ring pliers. Be
careful not to d8mage the rotor pulley and com-
pressor.
SNAP RING BR6place.
Remove the rotor pulley from the shaft with the
tools. Be sure the claws ot the puller are on the back
of the rotor pulley, not on the belt area; otherwise
the rotor pulley can be damaged.
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