Dodge Ram Truck 1500-2500-3500. Manual — part 1777
Handle C-4171
Dial Caliper - C-4962
Spring Compressor and Alignment Shaft - 6227
Gauge Bar - 6311
Gauge - 6312
Retainer - 6583
Installer - 8114
Socket, TRS Mounting Bracket - 8581
Installer, Seal - 9037
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AUTOMATIC TRANSMISSION - 48RE - SERVICE INFORMATION
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ACCUMULATOR
DESCRIPTION
The accumulator (1) is a hydraulic device that has the
sole purpose of cushioning the application of a band
or clutch. The accumulator consists of a dual-land pis-
ton (1) and a spring (2) located in a bore in the trans-
mission case.
Diesel version shown.
The 3-4 (1) accumulator is located in a housing (2)
attached to the side of the valve body.
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OPERATION
Both the accumulator and the 3-4 accumulator func-
tion the same. Line pressure (1) is directed to the
small end of the piston when the transmission is
placed into a DRIVE position, bottoming it against the
accumulator plate.
Diesel version shown.
When the 1-2 upshift occurs, line pressure (2) is
directed to the large end of the piston and then to the
kickdown servo. As the line pressure reaches the
accumulator, the combination of spring pressure and
line pressure forces the piston away from the accumu-
lator plate. This causes a balanced pressure situation,
which results in a cushioned band application. After
the kickdown servo has become immovable, line pres-
sure will finish pushing the accumulator up into its
bore (1). When the large end of the accumulator pis-
ton 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 piston if chipped
or cracked.
Check condition of the accumulator inner and outer springs. Replace the springs if the coils are cracked, distorted
or collapsed.
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BANDS
DESCRIPTION
KICKDOWN (FRONT) BAND
The kickdown, or “front”, band (1) holds the common
sun gear of the planetary gear sets. The front (kick-
down) 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 “rear”, band (4) 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-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 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 typically done by an apply lever and link bar.
LOW/REVERSE (REAR) BAND
The rear band holds the rear planet carrier stationary by being mounted around and applied to the low/reverse
drum.
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