Modulator Test; High Line Pressure Check; Vacuums Diaphragm Leak Test; Plunger Travel And Vacuum Holding Test - Jeep 1979 CJ-5 Technical & Service Manual

AUTOMATIC TRANSMISSION 20-11
Hydraulic Pressure Test Analysis
1
2
3 4
5 6
7
8
M A L F U N C T I O N
N E U T R A L
BRAKES
APPLIED
1000 RPM
D R I V E
I D L E
D R I V E
BRAKES
A P P L I E D
1000 RPM
D R I V E - 1
BRAKES
APPLIED
1000 RPM
REVERSE
B R A K E S
A P P L I E D
1000 RPM
D R I V E - B R A K E S
APPLIED 1000 RPM
D E T E N T
SWITCH A C T I V A T E D
PRESSURE DROP
OCCURS W H I L E
E N G I N E RPM
INCREASES F R O M
1000 T O 3 0 0 0 RPM
WHEELS FREE
T O M O V E *
D R I V E
3 0 M P H
CLOSED
T H R O T T L E
POSSIBLE CAUSE
OF M A L F U N C T I O N
M A L F U N C T I O N
O I L
PRESSURE
O I L
PRESSURE
O I L
PRESSURE
O I L
PRESSURE
O I L
PRESSURE
O I L
PRESSURE
PRESSURE DROP
OCCURS W H I L E
E N G I N E RPM
INCREASES F R O M
1000 T O 3 0 0 0 RPM
WHEELS FREE
T O M O V E *
O I L
PRESSURE
POSSIBLE CAUSE
OF M A L F U N C T I O N
NO 1-2 UPSHIFT
A N D / O R D E L A Y E D
UPSHIFT
N O R M A L N O R M A L N O R M A L
N O R M A L
N O R M A L N O R M A L
10 PSI DROP
OR M O R E
N O R M A L
M A L F U N C T I O N I N
C O N T R O L V A L V E ASSY.
NO 1-2 UPSHIFT
A N D / O R D E L A Y E D
UPSHIFT
N O R M A L N O R M A L N O R M A L N O R M A L N O R M A L N O R M A L
10 PSI D R O P
O R M O R E (69 KPa)
N O R M A L
M A L F U N C T I O N I N
G O V E R N O R OR
G O V E R N O R F E E D
SYSTEM
NO 1-2 UPSHIFT
A N D / O R D E L A Y E D
UPSHIFT
N O R M A L H I G H
H I G H
N O R M A L N O R M A L N O R M A L DROP H I G H
M A L F U N C T I O N I N
D E T E N T S Y S T E M
NO 1-2 UPSHIFT
A N D / O R D E L A Y E D
UPSHIFT
H I G H H I G H H I G H N O R M A L H I G H
- - - M A L F U N C T I O N I N
M O D U L A T O R OR
V A C U U M F E E D SYSTEM
T O M O D U L A T O R
S L I P P I N G - R E V E R S E N O R M A L N O R M A L
N O R M A L N O R M A L
LOW N O R M A L DROP N O R M A L
O I L LEAK I N F E E D
S Y S T E M T O T H E
D I R E C T C L U T C H
SLIPPING—1ST G E A R N O R M A L
LOW T O
N O R M A L
LOW T O
N O R M A L
LOW T O
N O R M A L
N O R M A L
LOW T O
N O R M A L
-
LOW T O
N O R M A L
O I L LEAK IN F E E D
S Y S T E M T O T H E
F O R W A R D C L U T C H
N O T D E T E N T
DOWNSHIFTS
N O R M A L
N O R M A L
N O R M A L N O R M A L N O R M A L LOW
N O R M A L N O R M A L
M A L F U N C T I O N I N
D E T E N T S Y S T E M
* D R I V E R A N G E , V A C U U M L I N E D I S C O N N E C T E D F R O M M O D U L A T O R . J 4 3 0 0 9
N O T E : A D A S H (-) I N T H E A B O V E C H A R T M E A N S T H A T T H E O I L PRESSURE R E A D I N G H A S N O M E A N I N G U N D E R T H E TEST C O N D I T I O N .
governor pipe or screen in control valve or case, or gover-
nor pipes loose in case holes.
(12) If line pressures are high, proceed to High Line
Pressure Check.
High Line Pressure Check
On vehicles with an EGR valve, the throttle is open
enough in D-range at 1000 rpm to cause the EGR valve
to open. When the valve opens, exhaust gas enters, the
intake manifold and decreases manifold vacuum. When
manifold vacuum is decreased, transmission line pres-
sure increases accordingly and may exceed the upper
specification limit. For this reason, if high line pressures
are obtained, proceed as follows:
(1) Disconnect and plug EGR vacuum line at EGR
valve.
(2) Recheck line pressures according to test being
performed.
(3) If line pressures are still high, connect Vacuum
Tester J-23738 to modulator and apply 20 inches of vac-
uum (67.3 kPa) to modulator.
(4) Recheck line pressures according to test being
performed and note following:
(a) If line pressures are still high, consult diag-
nosis charts and guides for probable cause.
(b) If line pressures are normal with external
vacuum applied, check engine vacuum and vacuum sys-
tems for leaks.
(5) Remove test gauges and tachometer and lower
vehicle.
(6) Perform repairs as necessary.
10IULIT0ITEST
Vacuum Diaphragm Leak Test
(1) Check for presence of transmission fluid in mod-
ulator using pipe cleaner. Insert pipe cleaner into modu-
lator vacuum connector pipe as far as possible.
Withdraw pipe cleaner and check for presence of trans-
mission fluid on pipe cleaner.
(2) Replace modulator if fluid is found in connector
pipe (fig. 2C-4). Transmission fluid may be lost through
diaphragm and burned in engine.
N O T E : Gasoline or water condensation may settle in
the vacuum side of the modulator. If condensation is
found but without the presence of transmission fluid, do
not replace the modulator.
Plunger Travel and Vacuum Holding Test
(1) Connect V a c u u m Test Tool J-23738 to
modulator.
(2) Slowly apply maximum of 21 inches' vacuum
and note when modulator plunger travel begins and
ends. On models with 258/304 CID engines (transmis-
sion models JC, JS, JK), plunger travel should begin at
approximately 16 inches vacuum and end at approx-
imately 21 inches. On models with 360 CID engine
(transmission • models JR, JM), plunger travel should
begin at approximately 12 inches vacuum and end at
approximately 16 inches.