2001 DODGE RAM Ac control

VALVE BODY
DESCRIPTION
The valve body consists of a cast aluminum valve
body, a separator plate, and transfer plate. The valve
body contains valves and check balls that control
fluid delivery to the torque converter clutch, bands,
and frictional clutches. The valve body contains the
following components (Fig. 244), (Fig. 245), (Fig.
246), and (Fig. 247):
²Regulator valve
²Regulator valve throttle pressure plug
²Line pressure plug and sleeve
²Kickdown valve
²Kickdown limit valve
²1-2 shift valve
²1-2 control valve
²2-3 shift valve²2-3 governor plug
²3-4 shift valve
²3-4 timing valve
²3-4 quick fill valve
²3-4 accumulator
²Throttle valve
²Throttle pressure plug
²Switch valve
²Manual valve
²Converter clutch lock-up valve
²Converter clutch lock-up timing Valve
²Shuttle valve
²Shuttle valve throttle plug
²Boost Valve
²10 check balls
By adjusting the spring pressure acting on the reg-
ulator valve, transmission line pressure can be
adjusted.
Fig. 244 Upper Housing Control Valve Locations
1 - UPPER HOUSING 8 - MANUAL VALVE
2 - REGULATOR VALVE 9 - 1-2 GOVERNOR PLUG
3 - SWITCH VALVE 10 - GOVERNOR PLUG COVER
4 - REGULATOR VALVE SPRING 11 - THROTTLE PLUG
5 - KICKDOWN VALVE 12 - 2-3 GOVERNOR PLUG
6 - KICKDOWN DETENT 13 - SHUTTLE VALVE PRIMARY SPRING
7 - THROTTLE VALVE AND SPRING
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 263

Fig. 246 Upper Housing Shift Valve and Pressure Plug Locations
1 - UPPER HOUSING 8 - RETAINER
2 - 1-2 SHIFT VALVE AND SPRING 9 - 1-2 SHIFT CONTROL VALVE AND SPRING
3 - 2-3 SHIFT VALVE AND SPRING 10 - PRESSURE PLUG COVER
4 - 2-3 THROTTLE PLUG 11 - LINE PRESSURE PLUG
5 - LIMIT VALVE HOUSING 12 - PLUG SLEEVE
6 - LIMIT VALVE COVER 13 - THROTTLE PRESSURE SPRING AND PLUG
7 - LIMIT VALVE AND SPRING
BR/BEAUTOMATIC TRANSMISSION - 42RE 21 - 265
VALVE BODY (Continued)

REGULATOR VALVE
The pressure regulator valve is needed to control
the hydraulic pressure within the system and reduce
the amount of heat produced in the fluid. The pres-
sure regulator valve is located in the valve body near
the manual valve. The pressure regulator valve train
controls the maximum pressure in the lines by
metering the dumping of fluid back into the sump.
Regulated pressure is referred to as ªline pressure.º
The regulator valve (Fig. 248) has a spring on one
end that pushes the valve to the left. This closes a
dump (vent) that is used to lower pressure. The clos-
ing of the dump will cause the oil pressure to
increase. Oil pressure on the opposite end of the
valve pushes the valve to the right, opening the
dump and lowering oil pressure. The result is spring
pressure working against oil pressure to maintain
the oil at specific pressures. With the engine run-
ning, fluid flows from the pump to the pressure reg-
ulator valve, manual valve, and the interconnected
circuits. As fluid is sent through passages to the reg-
ulator valve, the pressure pushes the valve to the
right against the large spring. It is also sent to the
reaction areas on the left side of the throttle pressure
plug and the line pressure plug. With the gear selec-
tor in the PARK position, fluid recirculates through
the regulator and manual valves back to the sump.Meanwhile, the torque converter is filled slowly. In
all other gear positions (Fig. 249), fluid flows
between two right side lands to the switch valve and
torque converter. At low pump speeds, the flow is
controlled by the pressure valve groove to reduce
pressure to the torque converter. After the torque
converter and switch valve fill with fluid, the switch
valve becomes the controlling metering device for
torque converter pressure. The regulator valve then
begins to control the line pressure for the other
transmission circuits. The balance of the fluid pres-
sure pushing the valve to the right and the spring
pressure pushing to the left determines the size of
the metering passage at land #2 (land #1 being at
the far right of the valve in the diagram). As fluid
leaks past the land, it moves into a groove connected
to the filter or sump. As the land meters the fluid to
the sump, it causes the pressure to reduce and the
spring decreases the size of the metering passage.
When the size of the metering passage is reduced,
the pressure rises again and the size of the land is
increased again. Pressure is regulated by this con-
stant balance of hydraulic and spring pressure.
The metering at land #2 establishes the line pres-
sure throughout the transmission. It is varied accord-
ing to changes in throttle position and the
transmission's internal condition within a range of
Fig. 248 Regulator Valve in PARK Position
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VALVE BODY (Continued)

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)

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)

SWITCH VALVE
When the transmission is in Drive Second before the
TCC application occurs (Fig. 263), the pressure regula-
tor valve is supplying torque converter pressure to the
switch valve. The switch valve directs this pressure
through the transmission input shaft, into the con-
verter, through the converter, back out between the
input shaft and the reaction shaft, and back up to the
switch valve. From the switch valve, the fluid pressure
is directed to the transmission cooler, and lubrication
pressure returns from the cooler to lubricate different
portions of the transmission.Once the TCC control valve has moved to the right
(Fig. 264), line pressure is directed to the tip of the
switch valve, forcing the valve to the right. The switch
valve now vents oil from the front of the piston in the
torque converter, and supplies line pressure to the (rear)
apply side of the torque converter piston. This pressure
differential causes the piston to apply against the fric-
tion material, cutting off any further flow of line pres-
sure oil. After the switch valve is shuttled right
allowing line pressure to engage the TCC, torque con-
verter pressure is directed past the switch valve into
the transmission cooler and lubrication circuits.
Fig. 263 Switch Valve-Torque Converter Unlocked
21 - 278 AUTOMATIC TRANSMISSION - 42REBR/BE
VALVE BODY (Continued)

MANUAL VALVE
The manual valve (Fig. 265) is a relay valve. The
purpose of the manual valve is to direct fluid to the
correct circuit needed for a specific gear or driving
range. The manual valve, as the name implies, is
manually operated by the driver with a lever located
on the side of the valve body. The valve is connected
mechanically by either a cable or linkage to the gear-
shift mechanism. The valve is held in each of its
positions by a spring-loaded roller or ball that
engages the ªroostercombº of the manual valve lever.
CONVERTER CLUTCH LOCK-UP VALVE
The torque converter clutch (TCC) lock-up valve
controls the back (ON) side of the torque converter
clutch. When the PCM energizes the TCC solenoid to
engage the converter clutch piston, pressure is
applied to the TCC lock-up valve which moves to the
right and applies pressure to the torque converter
clutch.
CONVERTER CLUTCH LOCK-UP TIMING VALVE
The torque converter clutch (TCC) lock-up timing
valve is there to block any 4-3 downshift until the
TCC is completely unlocked and the clutch is disen-
gaged.
SHUTTLE VALVE
The assembly is contained in a bore in the valve
body above the shift valves. When the manual valve
is positioned in the Drive range, throttle pressure
acts on the throttle plug of the shuttle valve (Fig.
257) to move it against a spring, increasing the
spring force on the shuttle valve. During a part or
full throttle 1-2 upshift, the throttle plug is bottomed
by throttle pressure, holding the shuttle valve to the
right against governor pressure, and opening a
by±pass circuit. The shuttle valve controls the qual-
ity of the kickdown shift by restricting the rate of
fluid discharge from the front clutch and servo
release circuits. During a 3-2 kickdown, fluid dis-
charges through the shuttle by-pass circuit. When
the shuttle valve closes the by-pass circuit, fluid dis-
charge is restricted and controlled for the application
of the front band. During a 2-3 ªlift footº upshift, the
shuttle valve by-passes the restriction to allow full
fluid flow through the by-pass groove for a faster
release of the band.
Fig. 265 Manual Valve
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VALVE BODY (Continued)

Fig. 283 Upper Housing Control Valve Locations
1 - UPPER HOUSING 8 - MANUAL VALVE
2 - REGULATOR VALVE 9 - 1-2 GOVERNOR PLUG
3 - SWITCH VALVE 10 - GOVERNOR PLUG COVER
4 - REGULATOR VALVE SPRING 11 - THROTTLE PLUG
5 - KICKDOWN VALVE 12 - 2-3 GOVERNOR PLUG
6 - KICKDOWN DETENT 13 - SHUTTLE VALVE PRIMARY SPRING
7 - THROTTLE VALVE AND SPRING
Fig. 284 Accumulator Housing Screw Locations
1 - LOOSEN THIS SCREW
2 - REMOVE THESE SCREWS
3 - 3-4 ACCUMULATOR HOUSINGFig. 285 3-4 Shift And Converter Clutch Valve
Springs And Plug
1 - ACCUMULATOR HOUSING
2 - CONVERTER CLUTCH VALVE SPRING
3 - CLUTCH VALVE PLUG
4 - 3-4 SHIFT VALVE SPRING
21 - 286 AUTOMATIC TRANSMISSION - 42REBR/BE
VALVE BODY (Continued)