Cadillac 60 Series 1963 Shop Manual page 94

HYDRA-MATIC TRANSMISSION
6-1
GENERAL DESCRIPTION
A controlled coupling Hydra-Matic transmission
is used as standard equipment on all 1963 Cadillac
cars. Two models of this transmission are used
to meet the requirements of the various series
cars.
The transmission used on all 1963 model 60 and
62 series cars is identified by a black name plate
attached to the lower left hand corner of the
transmission case rear face. The serial num-
ber on these transmissions is preceded by the
letter C.
Transmissions used on 75 series cars and the
commercial chassis have an oil pump of slightly
greater capacity to meet the greater cooling re-
quirements on these heavier cars. These trans-
missions are identified by an orange name plate
with the letters CA preceding the serial number.
The oil cooler for the 1963 transmission is
located in the lower tank of the radiator. Oil
from the pump passes through the cooler and then
back to the main fluid coupling.
The oil intake system of the 1963 transmission
incorporates a paper element type oil strainer on
the intake pipe. An internal by-pass is provided in
the strainer which permits increased oil flow
during cold operation when the oil is heavier. The
strainer should be replaced every 30,000 miles,
or in any case, where a major transmission fail-
ure has occurred.
PRINCIPLES OF OPERATION
The 1963 Cadillac Hydra-Matic transmission
has four forward speeds and one reverse. The
gear reductions required to obtain the various
speeds are provided by planetary gear sets.
Front Unit (Fig. 6-1)
In the front unit, the internal gear of the plane-
tary gear set is the driving member and the sun
gear is the reaction member. When power is
applied to the internal gear with the front unit
coupling empty, the sun gear is held stationary by
the front sprag and the planet carrier rotates
around the sun gear. This provides 1.55 to 1
reduction.
When the front unit coupling is filled with oil,
the sun gear and internal gear are driven at the
same speed and the planetary gearset rotates as
a unit, providing direct drive.
Rear Unit (Fig. 6-1)
Power from the front unit is transmitted to the
rear unit through two shafts: the intermediate
shaft and the mainshaft. Power is transmitted
from the front unit planet carrier through the
intermediate shaft to the rear unit hub. Power
from the front unit planet carrier is directed
through the main fluid coupling to the main shaft
and then to the sun gear of the rear planetary
gearset.
With the rear unit clutch released, the rear
internal gear (rear unit drum) is held stationary
by the rear sprag, which in turn is held stationary
by the neutral clutch. Power applied to the sun
gear causes the planet carrier to rotate around
the internal gear, providing 2.55 to 1 reduction.
When the rear unit clutch is applied, the rear
hub and drum are locked together and the internal
gear and sun gear are driven at the same speed.
The planetary gearset rotates as a unit providing
direct drive.
Reverse Unit (Fig. 6-1)
Reverse is obtained through a third planetary
gearset. The sun gear, connected to the rear unit
internal gear, is the driving member of the re-
verse unit gearset, and the reverse internal gear
is the reaction member.
The internal gear is normally free-wheeling so
that the reverse gearset is idling. When the
transmission selector is moved to the REVERSE
position, the reverse clutch locks the internal
gear to the case and the neutral clutch is re-
leased. With the reverse internal gear locked and
the rear unit idling, the reverse planet carrier is
turned in the reverse direction with 2.42 to 1
reduction.
Combined Operation
The combination of these units provides a
transmission from which four forward speeds and
one reverse speed are obtained.
1st speed is obtained by placing the front and
rear units in reduction. The 1.55 to 1 reduction
of the front unit combined with the 2.55 to 1