Chevrolet Light Duty Truck 1973, Руководство по обслуживанию

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A U T O M A T IC T R A N S M IS S I O N 7 A -79
Minimum Maximum
L2-2nd Gear - Steady road load at approxim ately 25 mph
145 psi 155 psi
Gear
Selector Lever Position
Minimum Maximum
1st Drive
2nd
3rd
(“ Zero” throttle to full thro ttle................................. ............... 60
150
3rd
Drive Range, Zero Throttle at 30 m p h ............... ............... 60
Reverse Rev. (Zero to full throttle ....................................... ............... 95
260
Fig. 31T—Oil Pressure Check - Road or Normal Operating Conditions
Approxim ate
Altitude of Check
(Ft. above sea level)
Drive
Neutral
Park
LI
or
L2
Reverse
0 150 150 244
2,000 150 150
233
4,000 145
150 222
6,000 138 150 212
8,000 132 150 203
10,000 126 150 194
12,000 121 150 186
14,000 116 150 178
Drive, Neutral, Park
LI or L2 Reverse
60
150 107
Fig. 33T—Oil Pressure Check • Vehicle Stationary,
Vacuum Tube Connected
Fig. 32T—Oil Pressure Check • Vehicle Stationary,
Vacuum Tube Disconnected
far as possible and check for the presence of
transmission oil. If oil is found, replace the modulator.
Gasoline or water vapor may settle in the vacuum side of
the modulator. If this is found without the presence of
oil, the modulator should not be changed.
Atmospheric Leak Check
Apply a liberal coating of soap bubble solution to the
vacuum connector pipe seam, the crimped upper to lower
housing seam, and the threaded screw seal (Fig. 34T).
Using a short piece of rubber tubing apply air pressure
to the vacuum pipe by blowing into the tube and observe
for leak bubbles. If bubbles appear, replace the
modulator.
NOTE: Do not use any method other than
human lung power for applying air pressure,
as pressures over 6 psi may damage the
modulator.
Bellows Comparison Check
Using a comparison gauge, as shown in Figure 35T,
compare the load of a known good Hydra-Matic
modulator with the assembly in question.
a. Install the modulator that is known to be acceptable
on either end of the gauge (Fig. 36T).
b. Install the modulator in question on the opposite
end of the gauge. (Fig. 37T).
c. Holding the modulators in a horizontal position,
bring them together under pressure until either
modulator sleeve end just touches the line in the
center of the gauge (Fig. 38T). The gap between the
opposite modulator sleeve end and the gauge line
should then be 1/16" or less. If the distance is
greater than this amount, the modulator in question
should be replaced.
LIGHT DUTY TRUCK SERVICE MANUAL