2001 DODGE RAM Service Repair Manual

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Page 1905 of 2889

DODGE RAM 2001 Service Repair Manual Fig. 250 Regulator Valve in DRIVE Position
Fig. 251 Regulator Valve in REVERSE Position
21 - 270 AUTOMATIC TRANSMISSION - 42REBR/BE
VALVE BODY (Continued)

Page 1906 of 2889

DODGE RAM 2001 Service Repair Manual KICKDOWN VALVE
When the throttle valve is as far over to the left as
it can go, the maximum line pressure possible will
enter the throttle pressure circuit. In this case, throt-
tle pressure will equa

Page 1907 of 2889

DODGE RAM 2001 Service Repair Manual KICKDOWN LIMIT VALVE
The purpose of the limit valve is to prevent a 3-2
downshift at higher speeds when a part-throttle
downshift is not desirable. At these higher speeds
only a full throttle 3-2 down

Page 1908 of 2889

DODGE RAM 2001 Service Repair Manual 1-2 SHIFT VALVE
The 1-2 shift valve assembly (Fig. 255), or mecha-
nism, consists of: the 1-2 shift valve, governor plug,
and a spring on the end of the valve. After the man-
ual valve has been placed

1-2 SHIFT VALVE
The 1-2 shift valve assembly (Fig. 255), or mecha-
nism, consists of: the 1-2 shift valve, governor plug,
and a spring on the end of the valve. After the man-
ual valve has been placed into a forward gear range,
line pressure is directed to the 1-2 shift valve. As the
throttle is depressed, throttle pressure is applied to
the right side of the 1-2 shift valve assembly. With
throttle pressure applied to the right side of the
valve, there is now both spring pressure and throttle
pressure acting on the valve, holding it against the
governor plug. As the vehicle begins to move and
build speed, governor pressure is created and is
applied to the left of the valve at the governor plug.
When governor pressure builds to a point where it
can overcome the combined force of the spring and
throttle pressure on the other side of the valve, the
valve will begin to move over to the right. As the
valve moves to the right, the middle land of the valve
will close off the circuit supplying the throttle pres-
sure to the right side of the valve. When the throttlepressure is closed off, the valve will move even far-
ther to the right, allowing line pressure to enter
another circuit and energize the front servo, applying
the front band (Fig. 256).
The governor plug serves a dual purpose:
²It allows the shift valves to move either left or
right, allowing both upshifts and downshifts.
²When in a manual selection position, it will be
hydraulically ªblockedº into position so no upshift can
occur.
The physical blocking of the upshift while in the
manual ª1º position is accomplished by the directing
of line pressure between both lands of the governor
plug. The line pressure reacts against the larger land
of the plug, pushing the plug back against the end
plate overcoming governor pressure. With the combi-
nation of the line pressure and spring pressure, the
valve cannot move, preventing any upshift.
Fig. 255 1-2 Shift Valve-Before Shift
Fig. 256 1-2 Shift Valve-After Shift
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 273
VALVE BODY (Continued)

Page 1909 of 2889

DODGE RAM 2001 Service Repair Manual 1-2 SHIFT CONTROL VALVE
It contains a valve with four lands and a spring. It
is used as both a ªrelayº and ªbalancedº valve.
The valve has two specific operations (Fig. 257):
²Aid in quality of t

1-2 SHIFT CONTROL VALVE
It contains a valve with four lands and a spring. It
is used as both a ªrelayº and ªbalancedº valve.
The valve has two specific operations (Fig. 257):
²Aid in quality of the 1-2 upshift.
²Aid in the quality and timing of the 3-2 kick-
down ranges.
When the manual valve is set to the DRIVE position
and the transmission is in the first or second gear range,
1-2 shift control or ªmodulated throttle pressureº is sup-
plied to the middle of the accumulator piston by the 1-2
shift control valve. During the 1-2 upshift, this pressure
is used to control the kickdown servo apply pressure that
is needed to apply the kickdown and accumulator pis-
tons. Thus, the 1-2 shift point is ªcushionedº and the
quality is improved. During a WOT kickdown, kickdown
pressure is applied between the kickdown valve and the
1-2 shift control valve. This additional pressure is
directed to the 1-2 shift control's spring cavity, adding to
the spring load on the valve. The result of this increased
ªmodulatedº throttle pressure is a firmer WOT upshift.
2-3 SHIFT VALVE
The 2-3 shift valve mechanism (Fig. 258) consists of
the 2-3 shift valve, governor plug and spring, and a
throttle plug. After the 1-2 shift valve has completed its
operation and applied the front band, line pressure is
directed to the 2-3 shift valve through the connecting
passages from the 1-2 shift valve. The line pressure will
then dead±end at land #2 until the 2-3 valve is ready to
make its shift. Now that the vehicle is in motion andunder acceleration, there is throttle pressure being
applied to the spring side of the valve and between
lands #3 and #4.
As vehicle speed increases, governor pressure
increases proportionately, until it becomes great enough
to overcome the combined throttle and spring pressure
on the right side of the valve. Since the throttle pres-
sure end of the 2-3 shift valve is larger in diameter than
the 1-2 shift valve, the 2-3 shift will always happen at a
greater speed than the 1-2 shift. When this happens,
the governor plug is forced against the shift valve mov-
ing it to the right. The shift valve causes land #4 to
close the passage supplying throttle pressure to the 2-3
shift valve. Without throttle pressure present in the cir-
cuit now, the governor plug will push the valve over far
enough to bottom the valve in its bore. This allows land
#2 to direct line pressure to the front clutch.
After the shift (Fig. 259), line pressure is directed
to the land between the shift valve and the governor
plug, and to the release side of the kickdown servo.
This releases the front band and applies the front
clutch, shifting into third gear or direct drive. The
rear clutch remains applied, as it has been in the
other gears. During a manual ª1º or manual ª2º gear
selection, line pressure is sent between the two lands
of the 2-3 governor plug. This line pressure at the
governor plug locks the shift valve into the second
gear position, preventing an upshift into direct drive.
The theory for the blocking of the valve is the same
as that of the 1-2 shift valve.
Fig. 257 1-2 Shift Control Valve
21 - 274 AUTOMATIC TRANSMISSION - 42REBR/BE
VALVE BODY (Continued)

Page 1910 of 2889

DODGE RAM 2001 Service Repair Manual Fig. 258 2-3 Shift Valve-Before Shift
Fig. 259 2-3 Shift Valve-After Shift
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 275
VALVE BODY (Continued)

Page 1911 of 2889

DODGE RAM 2001 Service Repair Manual 3-4 SHIFT VALVE
The PCM energizes the overdrive solenoid during
the 3-4 upshift (Fig. 260). This causes the solenoid
check ball to close the vent port allowing line pres-
sure from the 2-3 shift valve

Page 1912 of 2889

DODGE RAM 2001 Service Repair Manual THROTTLE VALVE
In all gear positions the throttle valve (Fig. 262) is
being supplied with line pressure. The throttle valve
meters and reduces the line pressure that now
becomes throttle pressure. The

THROTTLE VALVE
In all gear positions the throttle valve (Fig. 262) is
being supplied with line pressure. The throttle valve
meters and reduces the line pressure that now
becomes throttle pressure. The throttle valve is
moved by a spring and the kickdown valve, which is
mechanically connected to the throttle. The larger
the throttle opening, the higher the throttle pressure
(to a maximum of line pressure). The smaller the
throttle opening, the lower the throttle pressure (to a
minimum of zero at idle). As engine speed increases,
the increase in pump speed increases pump output.
The increase in pressure and volume must be regu-
lated to maintain the balance within the transmis-
sion. To do this, throttle pressure is routed to the
reaction area on the right side of the throttle pres-
sure plug (in the regulator valve).
The higher engine speed and line pressure would
open the vent too far and reduce line pressure too
much. Throttle pressure, which increases with engine
speed (throttle opening), is used to oppose the move-
ment of the pressure valve to help control the meter-
ing passage at the vent. The throttle pressure is
combined with spring pressure to reduce the force of
the throttle pressure plug on the pressure valve. The
larger spring at the right closes the regulator valve
passage and maintains or increases line pressure.
The increased line pressure works against the reac-
tion area of the line pressure plug and the reactionarea left of land #3 simultaneously moves the regu-
lator valve train to the right and controls the meter-
ing passage.
The kickdown valve, along with the throttle valve,
serve to delay upshifts until the correct vehicle speed
has been reached. It also controls downshifts upon
driver demand, or increased engine load. If these
valves were not in place, the shift points would be at
the same speed for all throttle positions. The kick-
down valve is actuated by a cam connected to the
throttle. This is accomplished through either a link-
age or a cable. The cam forces the kickdown valve
toward the throttle valve compressing the spring
between them and moving the throttle valve. As the
throttle valve land starts to uncover its port, line
pressure is ªmeteredº out into the circuits and viewed
as throttle pressure. This increased throttle pressure
is metered out into the circuits it is applied to: the
1-2 and 2-3 shift valves. When the throttle pressure
is high enough, a 3-2 downshift will occur. If the
vehicle speed is low enough, a 2-1 downshift will
occur.
Fig. 262 Throttle Valve
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 277
VALVE BODY (Continued)

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