2003 DODGE RAM app

HYDRAULIC FLOW IN DRIVE SECOND GEAR (CONVERTER CLUTCH APPLIED)
21 - 360 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)

HYDRAULIC FLOW IN DRIVE THIRD GEAR (CONVERTER CLUTCH NOT APPLIED)
DRAUTOMATIC TRANSMISSION - 48RE 21 - 361
AUTOMATIC TRANSMISSION - 48RE (Continued)

HYDRAULIC FLOW IN DRIVE THIRD GEAR (CONVERTER CLUTCH APPLIED)
21 - 362 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)

HYDRAULIC FLOW IN DRIVE FOURTH GEAR (CONVERTER CLUTCH NOT APPLIED)
DRAUTOMATIC TRANSMISSION - 48RE 21 - 363
AUTOMATIC TRANSMISSION - 48RE (Continued)

HYDRAULIC FLOW IN DRIVE FOURTH GEAR (CONVERTER CLUTCH APPLIED)
21 - 364 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)

ACCUMULATOR
DESCRIPTION
The accumulator (Fig. 68) is a hydraulic device
that has the sole purpose of cushioning the applica-
tion of a band or clutch. The accumulator consists of
a dual-land piston and a spring located in a bore in
the transmission case. The 3-4 accumulator is located
in a housing attached to the side of the valve body
(Fig. 69).
Retainer, Detent Ball and Spring - 6583
Installer, Overdrive Piston Seal - 8114
Socket, TRS Mounting Bracket - 8581
Installer, Seal - 9037
Fig. 68 Accumulator
1 - ACCUMULATOR PISTON
2 - PISTON SPRING
Fig. 69 3-4 Accumulator and Housing
1 - ACCUMULATOR PISTON
2 - 3-4 ACCUMULATOR HOUSING
3 - TEFLON SEALS
4 - PISTON SPRING
5 - COVER PLATE AND SCREWS
21 - 372 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)

OPERATION
Both the accumulator and the 3-4 accumulator
function the same. Line pressure is directed to the
small end of the piston when the transmission is
placed into a DRIVE position (Fig. 70), bottoming it
against the accumulator plate. When the 1-2 upshift
occurs (Fig. 71), line pressure is directed to the large
end of the piston and then to the kickdown servo. As
the line pressure reaches the accumulator, the com-
bination of spring pressure and line pressure forces
the piston away from the accumulator plate. This
causes a balanced pressure situation, which results
in a cushioned band application. After the kickdown
servo has become immovable, line pressure will fin-
ish pushing the accumulator up into its bore. When
the large end of the accumulator piston is seated in
its bore, the band or clutch is fully applied.
NOTE: The accumulator is shown in the inverted
position for illustrative purposes.
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 spring. Replace
the spring if the coils are cracked, distorted or col-
lapsed.
BANDS
DESCRIPTION
KICKDOWN (FRONT) BAND
The kickdown, or ªfrontº, band (Fig. 72) 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).
Fig. 70 Accumulator in DRIVE - FIRST Gear Position
1 - LINE PRESSURE
Fig. 71 Accumulator in SECOND Gear Position
1 - BOTTOM OF BORE
2 - LINE PRESSURE
3 - SHUTTLE VALVE
DRAUTOMATIC TRANSMISSION - 48RE 21 - 373
ACCUMULATOR (Continued)

LOW/REVERSE (REAR) BAND
The low/reverse band, or ªrearº, band (Fig. 73) is sim-
ilar 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-wrap band design (the drum is
completely encompassed/wrapped by the band). The
double-wrap band provides 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 thefront 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.
LOW/REVERSE (REAR) BAND
The rear band holds the rear planet carrier sta-
tionary by being mounted around and applied to the
low/reverse drum.
ADJUSTMENTS
ADJUSTMENT - BANDS
FRONT BAND
The front (kickdown) band adjusting screw is
located on the left side of the transmission case
above the manual valve and throttle valve levers.
(1) Raise vehicle.
(2) Loosen band adjusting screw locknut (Fig. 74).
Then back locknut off 3-5 turns. Be sure adjusting
screw turns freely in case. Apply lubricant to screw
threads if necessary.
(3) Tighten band adjusting screw to 8 N´m (72 in.
lbs.) torque with Inch Pound Torque Wrench
C-3380-A, a 3-in. extension and an appropriate
TorxŸ socket.
CAUTION: If Adapter C-3705 is needed to reach the
adjusting screw, tighten the screw to only 5 N´m
(47-50 in. lbs.) torque.
(4)
Back off front band adjusting screw 1-3/4 turns.
(5) Hold adjuster screw in position and tighten
locknut to 41 N´m (30 ft. lbs.) torque.
(6) Lower vehicle.
Fig. 72 Front Band
1 - FRONT BAND
2 - TRANSMISSION HOUSING
Fig. 73 Rear Band
1 - ADJUSTING SCREW
2 - LOCKNUT
3 - LEVER
4 - REAR BAND
5 - REACTION PIN
6 - O-RINGS
7 - PIVOT PIN
Fig. 74 Front Band Adjustment Screw Location
1 - LOCK-NUT
2 - FRONT BAND ADJUSTER
21 - 374 AUTOMATIC TRANSMISSION - 48REDR
BANDS (Continued)