Chevrolet 1977 10 Series, Repair Manual, Page: 273 / 468

AUTOMATIC TRANSMISSION (200)7A-37
”0 " RING SEAL
INTERMEDIATE SERVO
COVER
INTERMEDIATE SERVO
PISTON ASSY.
CUP PLUG
SEAL
7A-1 5 0 A ~ l n s t a l l i n g I n t e rm e d i a t e Ser vo Piston and Cover
A s s e m b ly
Control Valve Assembly
Disassembly
NOTE:
As each valve train is removed, place the
individual valve train in the order that it is removed
and in a separate location relative to its position in the
valve body. None of the valves, bushings or springs are
interchangeable; some coiled pins are interchangeable.
Remove all coiled pins by pushing through from
the rough cast surface side of the control valve
assebmly, except the 2 pins which retain the throttle
valve and throttle valve plunger.
1. Remove the 4 check balls.
2. Position control valve assembly as shown in Fig. 7A-
152A.
3. Remove 1-2 accum ulator piston.
4. Remove manual valve from upper bore.
CAUTION: Some o f the coiled pins in the control
valve assembly have pressure against them.
Therefore, hold a shop towel over the bore while
removing the pin, to prevent possibly losing a bore
plug, spring, etc.
5. Remove coiled pin from upper right bore. Remove
2-3 throttle valve bushing 2-3 throttle valve spring, 2-3
throttle valve and 2-3 shift valve.
NOTE:
The 2-3 throttle valve spring and 2-3 throttle
valve may be inside the 2-3 throttle valve bushing.
6. From next bore down, remove coiled pin. Remove
1-2 throttle valve bushing, 1-2 throttle valve spring, 1-2
throttle valve and 1-2 shift valve.
NOTE:
The 1-2 throttle valve spring and the 1-2
throttle valve may be inside the 1-2 throttle valve
bushing.
7. From next bore down, remove coiled pin and bore
plug. Remove reverse boost spring and reverse boost valve.
8. Check the operation of the shift T.V. valve in the
next bore down, by moving the valve against the spring. If
it is necessary to remove the valve, proceed as follows: (Figs.
7A-153A and 7A-154A).
a. Remove coiled pin and place valve body on shop
towel with rough casting surface up.
b. Using needle nose pliers, compress the shift T.V.
spring by pushing on the shift T.V. valve; hold valve with
small screwdriver.
Fig. 7 A - 1 5 1 A —In s t a ll in g L o w and Reverse Clu tch H o u sin g to
Case Cu p Plug and Seal
c. Place 6.3mm (1 /4 ") rod, 9.5mm (3 /8 ") long, against
the end of the shift T.V. valve.
d. Prying on end of the rod with a large screwdriver,
remove small screwdriver and remove shift T.V. plug, shift
T.V. spring and shift T.V. valve.
e. Discard shift T.V. plug and remove 6.3mm (1 /4 ")
rod from shift T.V. bore.
9. From next bore down, remove outer coiled pin.
Remove the throttle valve plunger, bushing, throttle valve
spring and detent pin. Using a 1.5mm (1/16") alien wrench
with ground sides to fit inside the pin, remove the inner
coiled pin (Fig. 7A-155A). Remove the throttle valve.
10. From upper left bore, remove coiled pin,
intermediate boost spring and interm ediate boost valve.
11. From next bore down, remove coiled pin, low
overrun clutch spring and low overrun clutch valve.
12. From next bore down, remove coiled pin, direct
clutch exhaust spring and direct clutch exhaust valve.
13. From next bore down, remove coiled pin, valve bore
plug, 1-2 accum ulator valve and 1-2 accum ulator valve and
1-2 accum ulator valve spring.
Inspection
1. Wash control valve body, valves, springs, and other
parts in clean solvent and air dry.
2. Inspect 1-2 accum ulator piston for damage.
3. Inspect 1-2 accum ulator piston seal for damage and
free fitting groove. Do not remove seal unless replacing.
4. Inspect valve for scoring, cracks and free movement
in their bores.
5. Inspect bushings for cracks or scored bores.
6. Inspect valve body for cracks damage or scored
bores.
7. Inspect springs for distortion or collapsed coils.
8. Inspect bore plugs for damage.
Reassembly
NOTE:
Install all coiled pins from machined face side
except the coiled pin retaining the throttle valve
bushing, plunger, spring and detent pin. Install this
coiled pin from rough casting side. Coiled pins do not
fit flush on rough casting face.
1. Position control valve body as shown in Fig. 7A-
152A.