1935 Cadillac - GM Heritage Center

157
Two types of Synchro-mesh transmissions are
used. The conventional Cadillac rocking yoke
type transmission is used on all Cadillac models,
while the inertia type transmission in which the
synchronizing drums are operated by detent
springs is used on the LaSalle.
TRANSMISSION
General Description
The synchronizing mechanism in both type
transmissions consists primarily of two cone-type
friction clutches, one for second gear and one for
high gear. Each clutch consists of a sliding drum
lined with a bronze ring and a steel cone on the
gear.
The synchronizing drums in the Cadillac transmission
are operated by rocking yokes pivoted
on eccentrics which are fastened to adjusting
quadrants on the outside of the transmission case.
These quadrants are graduated as a guide to the
amount of movement. Moving these plates up or
down shortens or lengthens the yoke travel.
The rocking movement of the yokes is accomplished
through cams machined on the shifter
shafts. These cams engage the rollers of the two
plungers which can be moved up and down in
cylinders or dashpots, filled with oil, in the upper
part of the yokes.
Synchronization in the LaSalle transmission is
accomplished primarily by the use of flat detent
springs, located in the splines of the main shaft
under the high-and-second-speed coupling and
secondly, by bevel faced slots on the coupling coming
in contact with cams on the synchronizing
drum fingers. The slots in the coupling in passing
over these fingers produce the required pressure
on the drums to force them in contact with the
cones to equalize the speeds of the gears so that
engagement of them can be made quietly and
without clashing.
The synchronizing mechanism is not necessary
on the low and reverse gears because shifting into
the low and reverse speed positions is only required
when the car is standing still.
Helical gears are used to give complete running
silence in all forward speeds, low as well as second
and in the LaSalle transmission reverse as well.
The teeth of these gears are cut at an angle of 45
degrees (30° for low and reverse on later cars)
giving maximum quietness and wear, and are
accurately ground and lapped after hardening,
insuring quiet operation under all running conditions.
Gear silence is further assured in the Cadillac
transmission by the use of large anti-friction
bearings which hold the gears rigidly in alignment.
The constant-mesh gears on the main shaft run
on tapered roller bearings, while the main shaft
and countershaft are carried in large ball bearings.
The arrangement of the gear shift lever differs
in the Series 40 and 60 cars in that it is mounted
forward on the clutch housing. On all other cars
this lever is mounted on the transmission cover in
the conventional manner.
Two types of shifting mechanism are used on the
LaSalle transmission. On early cars, interlocking
plates are employed to operate the shifter yokes.
The interlocking plates are not used in later cars
and the gear shift lever operates in the shifter
shafts in the same manner as in the Cadillac transmission.
In the early LaSalle transmissions using the
interlocking plates, the shifter shafts are carried
in bosses on each side of the transmission case.
The low and reverse shaft is on the left, with the
shifter fork at the rear end; and the high and
second speed shaft is on the right, with the shifter
fork just ahead of the center.
The lower end of the control lever actuates the
shifter forks through the two interlocking plates
in the top cover. See Fig. 2.
Top plate moved toward
high-and second-speed
Fig. 2. Drawings showing action of interlock plate in
first type LaSalle transmission. The top view shows
the movement of these plates when shifting into low
or reverse speed and the bottom view shows their movement
when shifting into high or second (intermediate)
speed.