Buick LeSabre 1965 Service Manual page 302

5 - 8 8 DESCRIPTION & OPERATION SUPER TURBINE "400'
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Figure 5-215-1-2 Shift Valve and
1-2 Modulator Valve
c. Governor pressure which is
generated by the governor assem-
bly. Governor pressure tends to
decrease modulator pressure.
5. 1-2 Shift Valve
Controls the oil pressure that
causes the transmission to shift
from 1-2 or 2-1. Its operation
is controlled by governor pres-
sure, detent pressure, modulator
pressure, and a spring force. See
Figure 5-215.
6. 1-2 Regulator Valve
Regulates modulator pressure to
a pressure proportional to modu-
lator pressure, tending to keep
the 1-2 shift valve in the down-
shift position. See Figure 5-216.
Figure 5-217
7. 1-2 Detent Valve
Senses regulated modulator pres-
sure tending to hold the 1-2 shift
valve in the downshift position and
provides an area for detent pres-
sure for detent 2-1 shifts. See
Figure 5-217.
8. 2-3 Shift Valve
Controls the oil pressure that
causes the transmission to shift
from 2-3 or 3-2. Its operation
is controlled by modulator, inter-
mediate g o v e r n o r and detent
pressure as well as a spring
force. See Figure 5-218.
9. 2-3 Modulator Valve
Senses modulator pressure to ap-
ply a variable force proportional
Figure 5-220
to modulator pressure which
tends to hold the 2-3 shift valve
down-shifted. See Figure 5-220.
10. 3-2 Valve
Shuts off modulator p r e s s u r e
from acting on the shift valve
trains after the direct clutch has
been applied. This allows heavy
throttle operation in third speed
without downshifting. In third
speed detent pressure can be di-
rected to the shift valves to pro-
vide the downshift forces. See
Figure 5-221.
11. Detent Valve
Shifts when line oil is exhausted
at the end of the valve when the
detent solenoid is energized. This
directs detent pressure to the
1-2 and 2-3 modulator valves, and
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Figure 5-216
Figure 5-218 Figure 5-221