Dodge 2001 Ram 1500 Owner's Manual page 2086

BR/BE
VALVE BODY (Continued)
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.
255) 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 "lift foot" 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.
AUTOMATIC TRANSMISSION - 44RE
Fig. 263 Manual Valve
BOOST VALVE
The boost valve (Fig. 264) provides increased fluid
apply pressure to the overdrive clutch during 3-4
upshifts (Fig. 265), and when accelerating in fourth
gear. The boost valve also serves to increase line
pressure during torque converter lock-up.
Fig. 264 Boost Valve Before Lock-up
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