Pontiac FIREBIRD 1972 Service Manual page 359

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NON TYPE C SAFE-T-TRACK DIFFERENTIAL
DIFFERENTIAL CASE
(FLANGE HALF)
I
SIDE GEAR
P I N I O N CROSS SHAFT
FLANGED
CAP SCREW
Fig. 46-3 Exploded View of Four Pinion Safe-T-Track - A and G Series
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"P" Axle
IMPORTANT: Due to the material ormanufac- assembly and as noted above. It is similar in all respects
turing differences in the medium duty and to the conventional case assembly, with the addition of
hea vy duty axle parts, they should NEVER be brake cone behind each side gear. The frictional surface of
interchanged.
these cones consists of a coarse spiral thread that provides
passages for flow of lubricant. The cones are statically
A A N D G SERIES (P A N D K CODED AXLES) A N D
6 SERIES (B CODED AXLE)
With the exception of the "C" type axle, all rear axle parts
of cars equipped with the Safe- T-Track two pinion differ-
ential (Fig. 4B-2) o r the Safe-T-Track four pinion differen-
tial (Fig. 4B-3) are interchangeable with those equipped
with the conventional differential, which have the same
last letter in the three letter axle code, except for the case
ireloaded with springs (against the cone cavities in each
half of the case assembly) to provide an internal resistance
to differential action under low tractive conditions at one
rear wheel.
The case assembly is held together with eight bolts. In
addition to the above parts, it also houses the differential
pinion shaft, pinion gears, thrust washers and the two
piece spring thurst block (two pinion differential) or two
spring thrust plates (four pinion differential).
OPERATION
ALL SERIES are locked together and rotate at the same speed.
The Safe-T-Track differential operates in reverse and de-
celeration, as well as all forward speeds. Torque is applied
by the drive pinion to the ring gear, which is bolted to the
case assembly, thereby causing it to rotate. The preload
force from the springs, plus the inherent separating force
between the pinion gears and side gears as the case rotates,
forces the side gears against their respective clutch pack
or cone. Since each disc is alternately attached to the case
and side gear, which is splined to the axle shaft, each shaft
is frictionally connected to the case so the shafts, in effect,
When turning corners, the axles are automatically un-
locked as torque created by differential action overcomes
the frictional forces between the clutch discs o r cones,
allowing them to turn with respect to each other.
When the rear wheels are under conditions of extremely
unbalanced traction, such as one wheel on dry pavement
and the other on ice, wheel spin may occur if over-acceler-
ation is attempted. However, even when wheel spin does
occur, the major driving force is directed to the non-
spinning wheel.