Cadillac 54-6219 1954 Shop Manual page 290

HYDRA-MATIC DRIVE
Teak from the front servo valve body is permissible.
3. Front Band Release
Air pressure applied into this passage will not
actuate servo because apply piston is held in re
leased position by retracting spring. However, no
unusual escape of air should be emitted between
servo body and transmission case or around band
release cylinder, except that which would normally
leak past release piston ring gap.
4. Governor G-1 to 4-3 Valve
Air pressure applied here should not escape be
tween servo body and transmission case or from any
other passages on side of case except, possibly, a
very small amount from passage No. 2. A slight
leak from the front servo valve body is permissible.
When the overrun control valve is actuated,
a
slight click will be noticed.
5. Rear Band Release
Air pressure applied into this passage should
release the rear servo and band with no unusual
escape of air. A small amount of air will escape
through piston ring gaps but this should not be
enough to impair normal servo operation. Observe
area where servo body rests on case. 'There should
be no appreciable
amount of air escape at this
point. Check other passages on side of case for
interconnection. While a very small amount of air
may be emitted from passage No. 7, there should
be no blow-by from any other passage.
6. Rear Clutch Apply
Air pressure applied into this passage should
actuate rear clutch. As pressure is intermittently
applied, movement of the clutch piston should be
audible and, in most cases, can be felt by holding
rear drum firmly with free hand.
If an unusual amount of air is escaping around
oil delivery sleeve area, another check at this
point must be made after servos are removed to
observe more clearly, the point of leakage.
If a fog of oil is emitted from inside rear unit
drum assembly, accompanied by escape of a large
amount of air, leak is probably due to a faulty
rear clutch seal or oil delivery sleeve rear ring.
Escape of air from any other passage on side of
case is an indication of interconnecting passages.
7. Compensator to Front and Rear Servos
Air pressure applied into this passage should
actuate rear servo to tighten rear band which is
applied by spring pressure, and to actuate front
14-5
Fig. 14-3 Identification of Oil Passages