Dodge dakota 2002 Service Manual page 2047

21 - 208 AUTOMATIC TRANSMISSION - 46RE
FRONT SERVO (Continued)
OPERATION
The application of the piston is accomplished by
applying pressure between the two lands of the piston.
The pressure acts against the larger lower land to push
the piston downward, allowing the piston rod to extend
though its guide against the apply lever. Release of the
servo at the 2-3 upshift is accomplished by a combina-
tion of spring and line pressure, acting on the bottom of
the larger land of the piston. The small piston is used to
cushion the application of the band by bleeding oil
through a small orifice in the larger piston. The release
timing of the kickdown servo is very important to obtain
a smooth but firm shift. The release has to be very
quick, just as the front clutch application is taking
place. Otherwise, engine runaway or a shift hesitation
will occur. To accomplish this, the band retains its hold-
ing capacity until the front clutch is applied, giving a
small amount of overlap between them.
DISASSEMBLY
(1) Remove seal ring from rod guide (Fig. 108).
(2) Remove small snap-ring from servo piston rod.
Then remove piston rod, spring and washer from pis-
ton.
(3) Remove and discard servo component O-ring
and seal rings.
Fig. 108 Front Servo
1 - PISTON RINGS
2 - SERVO PISTON
3 - O-RING
4 - SNAP-RING
5 - PISTON ROD GUIDE
6 - SEAL RING
7 - SNAP-RING
8 - SERVO SPRING
9 - WASHER
10 - SPRING
11 - PISTON ROD
CLEANING
Clean the servo piston components (Fig. 109) with
solvent and dry them with compressed air.
Fig. 109 Front Servo
1 - VENT
2 - INNER PISTON
3 - PISTON
4 - SPRING
5 - RELEASE PRESSURE
6 - APPLY PRESSURE
7 - PISTON ROD
INSPECTION
Inspect the servo components (Fig. 110). Replace
the springs if collapsed, distorted or broken. Replace
the guide, rod and piston if cracked, bent, or worn.
Discard the servo snap-ring if distorted or warped.
Fig. 110 Front Servo
1 - PISTON RINGS
2 - SERVO PISTON
3 - O-RING
4 - SNAP-RING
5 - PISTON ROD GUIDE
6 - SEAL RING
7 - SNAP-RING
8 - SERVO SPRING
9 - WASHER
10 - SPRING
11 - PISTON ROD
DR