Chevrolet 30 Series 1967 Service Manual page 429

5. Leak at low servo piston rod (between rod and bore).
. Leak at valve body to case gasket.
6
7. Leak at valve body gaskets.
. Front pump clearances.
8
9. Check passages in transmission case for porosity.
• Manual "Low" Range Pressure Check
Connect a tachometer, apply the parking brake, place
the selector lever in "Low" range, and adjust the engine
speed to rpm with the car stationary.
1 0 0 0
Low servo apply (main line) pressure should be as
shown on the pressure check chart.
P ressures not within this range can indicate the fol­
POWERGLIDE BASIC PRESSURE (MAINLINE) CHECKS
Wide Open
Throttle
Upshift
16" Hg.
96 - 112 60 - 74
104 - 119 60 - 74
^Partially open throttle until vacuum reads 10" Hg.
Idle Pressure "Drive"
Range @
10" Hg.*
-
8 8 1 0 1
-
8 8 1 0 1
lowing possibilities:
1. Partially plugged oil suction screen.
2. Broken or damaged ring low servo.
3. Pressure regulator valve stuck.
4. Leak at valve body to case gasket.
5. Leak between valve body gaskets.
. Leak at servo center.
6
7. Front pump clearances.
• Drive Range Overrun (Coast) Pressure
With the vehicle coasting in "Drive" range at 20-25
MPH with engine vacuum at approximately 20" Hg., low
servo apply (main line) pressure should be as shown on
the pressure check chart.
Drive Range
Manual "Low"
Overrun (Coast)
Range @ 1000
@ 20-25 MPH
RPM
20" Hg. Approx.
124 - 139
124 - 139
CLUTCHES AND TRANSMISSIONS 7-43
Engines
L-230
L-250
48 - 54
L-292
283 V
48 - 54 327 V
CHEVROLET TRUCK SERVICE M ANUAL
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