Coil DODGE RAM 1500 1998 2.G Workshop Manual
Page 1692 of 2627
(2) Mark the pitman arm and shaft positions for
installation reference. Remove the nut and washer
from the pitman arm (Fig. 5). Remove the pitman
arm with Puller C-4150A.
INSTALLATION
(1) Align reference marks and install pitman arm.
(2) Install the lock washer and retaining nut on
the pitman shaft and tighten nut to 251 N´m (185 ft.
lbs.).
(3) Install the drag link to the pitman arm (Fig. 6).
Install the nut and tighten to 108 N´m (80 ft. lbs.).(4) Remove the supports and lower the vehicle to
the surface. Center steering wheel and adjust toe,
(Refer to 2 - SUSPENSION/WHEEL ALIGNMENT -
STANDARD PROCEDURE).
(5) After adjustment tighten tie rod adjustment
sleeve clamp bolts to 61 N´m (45 ft. lbs.).
NOTE: Position the clamp on the sleeve so retain-
ing bolt is located on the bottom side of the sleeve.
TIE ROD END
REMOVAL
(1) Remove tie rod nuts (Fig. 7).
(2) Remove tie rod from drag link and left knuckle
with Puller C-4150A.
INSTALLATION
(1) Install tie rod to the left steering knuckle and
drag link. Install the nuts and tighten to 108 N´m
(80 ft. lbs.).
(2) Remove the supports and lower the vehicle to
the surface. Center steering wheel and adjust toe,
(Refer to 2 - SUSPENSION/WHEEL ALIGNMENT -
STANDARD PROCEDURE).
(3) After adjustment tighten tie rod adjustment
sleeve clamp bolts to 61 N´m (45 ft. lbs.).
NOTE: Position the clamp on the sleeve so retain-
ing bolt is located on the bottom side of the sleeve.
Fig. 5 PITMAN ARM REMOVAL/INSTALLATION
1 - STEERING GEAR
2 - PITMAN ARM
3 - NUT
4 - WASHER
Fig. 6 PITMAN ARM INSTALLED
1 - DRAGLINK
2 - STEERING GEAR
3 - SWAYBAR
4 - NUT/WASHER
5 - PITMAN ARM
Fig. 7 TIE ROD ENDS
1 - NUT
2 - TIE ROD ENDS
DRLINKAGE - LINK/COIL 19 - 37
PITMAN ARM (Continued)
Page 1693 of 2627
TRACK BAR
REMOVAL
(1) Raise and support the axle.
(2) Remove the track bar bolts and nuts (Fig. 8).
(3) Remove the track bar (Fig. 8).
INSTALLATION
(1) Install the track bar.
(2) Install the new bolts and nuts. Tighten to 203
N´m (150 ft lbs.).
(3) Remove the supports under the axle and lower
the vehicle to the ground.
Fig. 8 TRACK BAR REMOVAL/INSTALLATION
1 - TRACK BAR
2 - BOLT
3 - NUT
19 - 38 LINKAGE - LINK/COILDR
Page 1694 of 2627
PUMP
TABLE OF CONTENTS
page page
PUMP
DESCRIPTION.........................39
OPERATION...........................40
DIAGNOSIS AND TESTING - PUMP LEAKAGE . 40
STANDARD PROCEDURE
STANDARD PROCEDURE - POWER
STEERING PUMP - INITIAL OPERATION....40
STANDARD PROCEDURE - FLUSHING
POWER STEERING SYSTEM............40
REMOVAL
REMOVAL - GAS......................41
REMOVAL - DIESEL...................41
INSTALLATION
INSTALLATION - GAS..................42
INSTALLATION - DIESEL................42
SPECIFICATIONS
TORQUE CHART......................42
FLUID
DESCRIPTION.........................43
STANDARD PROCEDURE - POWER
STEERING FLUID LEVEL CHECKING......43
FLUID COOLER
REMOVAL.............................43
INSTALLATION.........................43
HOSES - I.F.S.
REMOVAL
REMOVAL - RETURN HOSE - GEAR TO
COOLER............................44
REMOVAL - PRESSURE HOSE...........44
REMOVAL - RETURN HOSE - RESERVOIR
TO COOLER.........................44INSTALLATION
INSTALLATION - RETURN HOSE - GEAR TO
COOLER............................44
INSTALLATION - PRESSURE HOSE.......44
INSTALLATION - RETURN HOSE -
RESERVOIR TO COOLER...............44
HOSES - LINK/COIL
REMOVAL
REMOVAL - RETURN HOSE - GEAR TO
COOLER............................45
REMOVAL - PRESSURE HOSE...........45
REMOVAL - RETURN HOSE - RESERVOIR
TO COOLER.........................45
INSTALLATION
INSTALLATION - RETURN HOSE - GEAR TO
COOLER............................45
INSTALLATION - PRESSURE HOSE.......45
INSTALLATION - RETURN HOSE -
RESERVOIR TO COOLER...............45
POWER STEERING PRESSURE SWITCH
DESCRIPTION.........................46
OPERATION...........................46
REMOVAL - 3.7L & 5.7L..................46
INSTALLATION - 3.7L & 5.7L...............46
PULLEY
REMOVAL.............................47
INSTALLATION.........................47
RESERVOIR
REMOVAL.............................47
INSTALLATION.........................47
PUMP
DESCRIPTION
CAUTION: MOPARTATF+4 is to be used in the
power steering system. No other power steering or
automatic transmission fluid is to be used in the
system. Damage may result to the power steering
pump and system if any other fluid is used, and do
not overfill.The pump is connected to the steering gear via the
pressure hose and the return hose. The pump shaft
has a pressed-on pulley that is belt driven by the
crankshaft pulley.
All vehicles are equipped with a power steering
fluid cooler.
NOTE: Power steering pumps are not interchange-
able with pumps installed on other vehicles.
DRPUMP 19 - 39
Page 1700 of 2627
HOSES - LINK/COIL
REMOVAL
REMOVAL - RETURN HOSE - GEAR TO
COOLER
(1) Drain and siphon the power steering system.
(2) Raise and support the vehicle.
(3) Disconnect the return hose at the cooler.
(4) Disconnect the return hose at the gear (Fig. 7).
(5) Remove the return hose from the routing clamp
at the fan shroud and then remove from the vehicle.
REMOVAL - PRESSURE HOSE
(1) Drain and siphon the power steering system.
(2) Raise and support the vehicle.
(3) Disconnect the pressure hose at the pump.
(4)
Disconnect the pressure hose at the gear (Fig. 8).
(5) Remove the pressure hose from the vehicle.
REMOVAL - RETURN HOSE - RESERVOIR TO
COOLER
(1) Drain and siphon the power steering system.
(2) Disconnect the return hose at the reservoir.
(3) Raise and support the vehicle.
(4) Remove the return hose from the routing clamp
at the fan shroud.
(5) Disconnect the return hose at the cooler.
(6) Remove the hose from the vehicle.
INSTALLATION
INSTALLATION - RETURN HOSE - GEAR TO
COOLER
(1) Install the return hose to the vehicle.
(2) Reconnect the return hose at the cooler.
(3) Reconnect the return hose at the gear. Tighten
the hose to 51 N´m (38 ft. lbs.) (Fig. 7).
(4) Reattach the hose to the routing clip at the fan
shroud.
(5) Remove the support and lower the vehicle.
(6) Refill the power steering system,(Refer to 19 -
STEERING/PUMP - STANDARD PROCEDURE).
INSTALLATION - PRESSURE HOSE
NOTE: Be sure to align the pressure hose so it
does not contact the fan shroud or the frame rail.
(1) Install the pressure hose to the vehicle.
(2) Reconnect the pressure hose at the gear.
Tighten the hose to 32 N´m (23 ft. lbs.) (Fig. 8).
(3) Reconnect the pressure hose at the pump.
Tighten the hose to 36 N´m (27 ft. lbs.).
(4) Remove the support and lower the vehicle.
(5) Refill the power steering system,(Refer to 19 -
STEERING/PUMP - STANDARD PROCEDURE).
INSTALLATION - RETURN HOSE - RESERVOIR
TO COOLER
(1) Install the return hose to the vehicle.
(2) Reconnect the return hose at the cooler.
(3) Reattach the hose to the routing clip at the fan
shroud.
Fig. 7 POWER STEERING HOSES TO STEERING GEAR
1 - HIGH PRESSURE HOSE
2 - RETURN HOSE
3 - STEERING GEAR
Fig. 8 HOSES INSTALLED
1 - LOWER COUPLING BOLT
2 - HIGH PRESSURE HOSE
3 - RETURN HOSE
4 - STEERING GEAR
5 - PITMAN ARM
DRPUMP 19 - 45
Page 1701 of 2627
(4) Remove the support and lower the vehicle.
(5) Reconnect the return hose at the reservoir.
(6) Refill the power steering system,(Refer to 19 -
STEERING/PUMP - STANDARD PROCEDURE).
POWER STEERING PRESSURE
SWITCH
DESCRIPTION
A pressure sensing switch is used in the power
steering system. It is mounted on the high-pressure
steering hose (Fig. 9). This switch will be used with
both 3.7L and 5.7L engines. There is no pressure
switch used for the 4.7L or the 5.9L pump.
OPERATION
The switch is used on the 3.7L V-6 & 5.7L V-8
engines.
The power steering pressure switch provides an
input to the Powertrain Control Module (PCM). This
input is provided during periods of high steering
pump load and low engine rpm; such as during park-
ing maneuvers. The PCM increases the idle speed
through the Idle Air Control (IAC) motor. This is
done to prevent the engine from stalling under the
increased load.
When steering pump pressure exceeds 3275 kPa
690 kPa (475 psi 100 psi), the Normally Closed
(NC) switch will open and the PCM will increase the
engine idle speed. This will prevent the engine from
stalling.
When pump pressure drops to approximately 1379
kPa (200 psi), the switch circuit will re-close and
engine idle speed will return to its previous setting.
REMOVAL - 3.7L & 5.7L
The power steering pressure switch is installed in
the power steering high-pressure hose (Fig. 9).
(1) Disconnect electrical connector from power
steering pressure switch.(2) Place a small container or shop towel beneath
switch to collect any excess fluid.
(3) Remove switch. Use back-up wrench on power
steering line to prevent line bending.
INSTALLATION - 3.7L & 5.7L
This switch is used only with the 3.7L V±6 and the
5.7L V-8 engines.
(1) Install power steering switch into power steer-
ing line.
(2) Tighten to 8±11 N´m (70±100 in. lbs.) torque.
(3) Connect electrical connector to switch.
(4) Check power steering fluid and add as neces-
sary.
(5) Start engine and again check power steering
fluid. Add fluid if necessary.
Fig. 9 PRESSURE SWITCH
1 - POWER STEERING PULLEY
2 - POWER STEERING PUMP HOUSING
3 - POWER STEERING FLUID RESERVOIR
4 - RETURN HOSE
5 - HIGH PRESSURE HOSE WITH PRESSURE SWITCH
19 - 46 PUMPDR
HOSES - LINK/COIL (Continued)
Page 1719 of 2627
INSPECTION
SHIFT LEVER ASSEMBLY
The shift lever assembly is not serviceable. Replace
the lever and shift tower as an assembly if the tower,
lever, lever ball or internal components are worn or
damaged.
SHIFT SHAFT AND FORKS
Inspect the shift fork interlock arms and synchro
sleeve contact surfaces (Fig. 48). Replace any fork
exhibiting wear or damage in these areas. Do not
attempt to salvage shift forks.
Check condition of the shift shaft detent plunger
and spring. The plunger should be smooth and free of
nicks or scores. The plunger spring should be
straight and not collapsed, or distorted. Minor
scratches or nicks on the plunger can be smoothed
with 320/400 grit emery soaked in oil. Replace the
plunger and spring if in doubt about condition. Check
condition of detent plunger bushings. Replace if dam-
aged.
Inspect shift shaft, shift shaft bushing, bearing,
shaft lever and lever bushing that fits over the lever.
Replace shaft if bent, cracked or severely scored.
Minor burrs, nicks or scratches can be smoothed off
with 320/400 grit emery cloth followed by polishing
with crocus cloth. Replace the shift shaft bushing or
bearing if damaged.Replace the shaft lever and bushing if either part
is deformed, or worn. Do not attempt to salvage these
parts as shift fork binding will occur. Replace the roll
pin that secures the lever to the shaft.
FRONT/REAR HOUSINGS AND BEARING
RETAINERS
Inspect the housings carefully. Look for cracks,
stripped threads, scored mating surfaces, damaged
bearing bores or worn dowel pin holes. Minor nicks
on mating surfaces can be dressed off with a fine file
or emery cloth. Damaged threads can be renewed by
either re-tapping or installing Helicoil inserts.
NOTE: The front housing contains the countershaft
front bearing race. The rear housing contains the
countershaft rear bearing race. These components
are NOT serviceable items. The front housing will
have to be replaced if the countershaft bearing race
is loose, worn or damaged. The rear housing will
have to be replaced if the countershaft rear bearing
race is loose, worn or damaged.
Inspect the input shaft bearing retainer. Be sure
the release bearing slide surface of the retainer is in
good condition. Minor nicks on the surface can be
smoothed off with 320/420 grit emery cloth and final
polished with oil coated crocus cloth. Replace the
retainer seal if necessary.
Fig. 48 Shift Forks And Shaft
1 - SHIFT SHAFT
2 - SHAFT LEVER
3 - SHAFT LEVER BUSHING4 - 3-4 SHIFT FORK
5 - 1-2 SHIFT FORK
6 - FIFTH-REVERSE SHIFT FORK
21 - 16 MANUAL TRANSMISSION - NV3500DR
MANUAL TRANSMISSION - NV3500 (Continued)
Page 1861 of 2627
STANDARD PROCEDURE - ALUMINUM
THREAD REPAIR
Damaged or worn threads in the aluminum trans-
mission case and valve body can be repaired by the
use of Heli-CoilsŸ, or equivalent. This repair con-
sists of drilling out the worn-out damaged threads.
Then tap the hole with a special Heli-CoilŸ tap, or
equivalent, and installing a Heli-CoilŸ insert, or
equivalent, into the hole. This brings the hole back to
its original thread size.
Heli-CoilŸ, or equivalent, tools and inserts are
readily available from most automotive parts suppli-
ers.
REMOVAL
NOTE: The overdrive unit can be removed and ser-
viced separately. It is not necessary to remove the
entire transmission assembly to perform overdrive
unit repairs.
(1) Disconnect battery negative cable.
(2) Raise vehicle.
(3) Remove the transfer case skid plate (Fig. 12), if
equipped.(4) Disconnect and lower or remove necessary
exhaust components.
(5) Remove engine-to-transmission struts.
(6) Remove starter motor. (Refer to 8 - ELECTRI-
CAL/STARTING/STARTER MOTOR - REMOVAL)
(7) Disconnect and remove the crankshaft position
sensor. (Refer to 14 - FUEL SYSTEM/FUEL INJEC-
TION/CRANKSHAFT POSITION SENSOR -
REMOVAL) Retain the sensor attaching bolts.
(8) If transmission is being removed for overhaul,
remove transmission oil pan, drain fluid and reinstall
pan.
(9) Remove torque converter access cover.
(10) Rotate crankshaft in clockwise direction until
converter bolts are accessible. Then remove bolts one
at a time. Rotate crankshaft with socket wrench on
dampener bolt.
(11) Mark propeller shaft and axle yokes for
assembly alignment. Then disconnect and remove
propeller shaft. On4x4models, remove both propel-
ler shafts. (Refer to 3 - DIFFERENTIAL & DRIV-
ELINE/PROPELLER SHAFT/PROPELLER SHAFT -
REMOVAL)
(12) Disconnect wires from the transmission range
sensor and transmission solenoid connector.
(13) Disconnect gearshift cable (Fig. 13) from the
transmission.
Fig. 12 Transfer Case Skid Plate
1 - FRAME RAIL
2 - SKID PLATE
3 - BOLTS (6)
Fig. 13 Gearshift Cable At Transmission
1 - GEARSHIFT CABLE
2 - TRANSMISSION MANUAL LEVER
3 - CABLE SUPPORT BRACKET
21 - 158 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)
Page 1869 of 2627
(33) Remove tools and remove servo piston and
spring.
(34) Compress rear servo piston with C-clamp and
Tool C-4470, or Valve Spring Compressor C-3422-B
(Fig. 39). Compress servo spring retainer only
enough to permit snap-ring removal.
(35) Remove servo piston snap-ring (Fig. 39). Start
one end of ring out of bore. Then carefully work
removal tool around back of snap-ring until free of
ring groove.Exercise caution when removing
snap-ring. Servo bore can be scratched or
nicked if care is not exercised.
(36) Remove tools and remove rear servo retainer,
spring and piston assembly.
CLEANING
Clean the case in a solvent tank. Flush the case
bores and fluid passages thoroughly with solvent.
Dry the case and all fluid passages with compressed
air. Be sure all solvent is removed from the case and
that all fluid passages are clear.
NOTE: Do not use shop towels or rags to dry the
case (or any other transmission component) unless
they are made from lint-free materials. Lint will stick
to case surfaces and transmission components and
circulate throughout the transmission after assem-
bly. A sufficient quantity of lint can block fluid pas-
sages and interfere with valve body operation.
Lubricate transmission parts with MopartATF +4,
Automatic Transmission fluid, during overhaul and
assembly. Use petroleum jelly to prelubricate seals,
O-rings, and thrust washers. Petroleum jelly can also
be used to hold parts in place during reassembly.
INSPECTION
Inspect the case for cracks, porous spots, worn
bores, or damaged threads. Damaged threads can be
repaired with Helicoil thread inserts. However, the
case will have to be replaced if it exhibits any type of
damage or wear.
Lubricate the front band adjusting screw threads
with petroleum jelly and thread the screw part-way
into the case. Be sure the screw turns freely.
Inspect the transmission bushings during overhaul.
Bushing condition is important as worn, scored bush-
ings contribute to low pressures, clutch slip and
accelerated wear of other components. However, do
not replace bushings as a matter of course. Replace
bushings only when they are actually worn, or
scored.
The use of crocus cloth is permissible where neces-
sary, providing it is used carefully. When used on
shafts, or valves, use extreme care to avoid rounding
off sharp edges. Sharp edges are vital as they pre-
vent foreign matter from getting between the valve
and valve bore.
Do not reuse oil seals, gaskets, seal rings, or
O-rings during overhaul. Replace these parts as a
matter of course. Also do not reuse snap rings or
E-clips that are bent or distorted. Replace these parts
as well.
ASSEMBLY
Do not allow dirt, grease, or foreign material to
enter the case or transmission components during
assembly. Keep the transmission case and compo-
nents clean. Also make sure the tools and workbench
area used for reassembly operations are equally
clean.
Shop towels used for wiping off tools and your
hands must be made fromlint freematerials. Lint
will stick to transmission parts and could interfere
with valve operation or even restrict fluid passages.
Lubricate transmission clutch and gear compo-
nents with MopartATF +4 during reassembly. Soak
clutch discs in transmission fluid before installation.
Use petroleum jelly on piston seals and o-rings to
ease installation. Petroleum jelly can also be used to
lubricate and hold thrust washers and plates in posi-
tion during assembly.
Do not use chassis grease, bearing grease,
white grease, or similar lubricants on any part.
These types of lubricants can eventually block or
restrict fluid passages and valve operation. Use
petroleum jelly only.
Do not force parts into place. The transmission
components and sub-assemblies are easily installed
by hand when properly aligned. If a part seems dif-
ficult to install, it is either misaligned or incorrectly
Fig. 39 Rear Servo Retaining Snap-Ring
1 - TOOL C-4470
2 - C-CLAMP
3 - REAR SERVO SPRING RETAINER
4 - RETAINER SNAP-RING
21 - 166 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)
Page 1897 of 2627
INSPECTION
Inspect the accumulator piston and seal rings.
Replace the seal rings if worn or cut. Replace the pis-
ton if chipped or cracked.
Check condition of the accumulator inner and
outer springs. Replace the springs if the coils are
cracked, distorted or collapsed.
BANDS
DESCRIPTION
KICKDOWN (FRONT) BAND
The kickdown, or ªfrontº, band (Fig. 70) holds the
common sun gear of the planetary gear sets. The
front (kickdown) band is made of steel, and faced on
its inner circumference with a friction-type lining.
One end of the band is anchored to the transmission
case, and the other is acted on with a pushing force
by a servo piston. The front band is a single-wrap
design (the band does not completely encompass/
wrap the drum that it holds).
LOW/REVERSE (REAR) BAND
The low/reverse band, or ªrearº, band (Fig. 71) is
similar in appearance and operation to the front
band. The rear band is slightly different in that it
does not use a link bar, but is acted directly on by
the apply lever. This is referred to as a double-wrapband design (the drum is completely encompassed/
wrapped by the band). The double-wrap band pro-
vides a greater holding power in comparison to the
single-wrap design.
OPERATION
KICKDOWN (FRONT) BAND
The kickdown band holds the common sun gear of
the planetary gear sets by applying and holding the
front clutch retainer, which is splined to the sun gear
driving shell, and in turn splined directly to the sun
gear. The application of the band by the servo is typ-
ically done by an apply lever and link bar.
Fig. 69 Accumulator in SECOND Gear Position
1 - BOTTOM OF BORE
2 - LINE PRESSURE
3 - SHUTTLE VALVE
Fig. 70 Front Band
1 - FRONT BAND
2 - TRANSMISSION HOUSING
Fig. 71 Rear Band
1 - ADJUSTING SCREW
2 - LOCKNUT
3 - LEVER
4 - REAR BAND
5 - REACTION PIN
6 - O-RINGS
7 - PIVOT PIN
21 - 194 AUTOMATIC TRANSMISSION - 48REDR
ACCUMULATOR (Continued)
Page 1955 of 2627
SHIFT MECHANISM
DESCRIPTION
The gear shift mechanism provides six shift posi-
tions which are:
²PARK (P)
²REVERSE (R)
²NEUTRAL (N)
²DRIVE (D)
²Manual SECOND (2)
²Manual LOW (1)
OPERATION
Manual LOW (1) range provides first gear only.
Overrun braking is also provided in this range. Man-
ual SECOND (2) range provides first and second gear
only.
DRIVE range provides first, second, third, and
overdrive fourth gear ranges. The shift into overdrive
fourth gear range occurs only after the transmission
has completed the shift into D third gear range. No
further movement of the shift mechanism is required
to complete the 3-4 shift.
The fourth gear upshift occurs automatically when
the overdrive selector switch is in the ON position.
No upshift to fourth gear will occur if any of the fol-
lowing are true:
²The transmission fluid temperature is below 10É
C (50É F) or above 121É C (250É F).
²The shift to third is not yet complete.
²Vehicle speed is too low for the 3-4 shift to occur.
²Battery temperature is below -5É C (23É F).
SOLENOID
DESCRIPTION
The typical electrical solenoid used in automotive
applications is a linear actuator. It is a device that
produces motion in a straight line. This straight line
motion can be either forward or backward in direc-
tion, and short or long distance.
A solenoid is an electromechanical device that uses
a magnetic force to perform work. It consists of a coil
of wire, wrapped around a magnetic core made from
steel or iron, and a spring loaded, movable plunger,
which performs the work, or straight line motion.
The solenoids used in transmission applications
are attached to valves which can be classified asnor-
mally openornormally closed. Thenormally
opensolenoid valve is defined as a valve which
allows hydraulic flow when no current or voltage is
applied to the solenoid. Thenormally closedsole-
noid valve is defined as a valve which does not allow
hydraulic flow when no current or voltage is applied
to the solenoid. These valves perform hydraulic con-trol functions for the transmission and must there-
fore be durable and tolerant of dirt particles. For
these reasons, the valves have hardened steel pop-
pets and ball valves. The solenoids operate the valves
directly, which means that the solenoids must have
very high outputs to close the valves against the siz-
able flow areas and line pressures found in current
transmissions. Fast response time is also necessary
to ensure accurate control of the transmission.
The strength of the magnetic field is the primary
force that determines the speed of operation in a par-
ticular solenoid design. A stronger magnetic field will
cause the plunger to move at a greater speed than a
weaker one. There are basically two ways to increase
the force of the magnetic field:
1. Increase the amount of current applied to the
coil or
2. Increase the number of turns of wire in the coil.
The most common practice is to increase the num-
ber of turns by using thin wire that can completely
fill the available space within the solenoid housing.
The strength of the spring and the length of the
plunger also contribute to the response speed possi-
ble by a particular solenoid design.
A solenoid can also be described by the method by
which it is controlled. Some of the possibilities
include variable force, pulse-width modulated, con-
stant ON, or duty cycle. The variable force and pulse-
width modulated versions utilize similar methods to
control the current flow through the solenoid to posi-
tion the solenoid plunger at a desired position some-
where between full ON and full OFF. The constant
ON and duty cycled versions control the voltage
across the solenoid to allow either full flow or no flow
through the solenoid's valve.
OPERATION
When an electrical current is applied to the sole-
noid coil, a magnetic field is created which produces
an attraction to the plunger, causing the plunger to
move and work against the spring pressure and the
load applied by the fluid the valve is controlling. The
plunger is normally directly attached to the valve
which it is to operate. When the current is removed
from the coil, the attraction is removed and the
plunger will return to its original position due to
spring pressure.
The plunger is made of a conductive material and
accomplishes this movement by providing a path for
the magnetic field to flow. By keeping the air gap
between the plunger and the coil to the minimum
necessary to allow free movement of the plunger, the
magnetic field is maximized.
21 - 252 AUTOMATIC TRANSMISSION - 48REDR