Reverse-Range Clutches, Left and Right

TM 9-2520-249-34&P

which causes the reversing action described in

Thrust washers (26 and 26.6) position the pinions and

paragraph 2-11 b, above. When the clutch is released,

absorb end-thrust forces. The spindles are pressed into

the carrier and locked in place with pins (26.8).

springs (17), acting against reaction disk (32), seat the

(3) Planetary carrier assembly (23, FO-6)

piston in its cavity in the bevel gear housing.

is supported by ball bearing (28) which is mounted on

the cross shaft. The outer circumference of the carrier

2-13.

Brakes and Brake Apply Components, Left

is splined to the internal splines of left reverse-range

and Right

clutch hub (19).

a. Description

b. Operation. (FO-6 and FO-9)

(1) Right and left brake assemblies are

(1) When the reverse-range clutch is

included in the transmission. Most components of one

engaged, carrier (24, FO-6) is prevented from turning.

assembly are identical to those of the other assembly.

Thus, the torque imparted by sun gear assembly (47) to

The components which are not identical differ only in

pinions (26.3) causes them to rotate on spindles (26.7)

that they are specifically designed for right- or left-side

which are held stationary within the housing. The

installation. The brake assemblies are located in the

rotating pinions, therefore, drive the ring gear (brake

right and left cavities of the bevel gear housing. The

hub 45) in the direction opposite to that of the sun gear.

brake apply components, located in the top cover

(2) Driven brake hub (45, FO-6), (reverse

assembly, are just above their respective brake

ring gear) is splined to steer planetary carrier (58) which,

assemblies. The brakes are mechanically applied. The

in turn, is splined to output shaft (54) Thus, the output

apply mechanism is connected, by external linkage, to a

shaft rotates in reverse at a speed reduction ratio of 2 to

single, foot operated pedal. The pedal and external

1. When the reverse-range clutch is released, reverse-

linkage are parts of the vehicle. The brakes are applied

range carrier (24) rotates freely.

together, through the external linkage. Their only

function is to slow, stop or hold the vehicle. Because of

2-12.

Reverse-Range Clutches, Left and Right

the close similarity of the right and left brake

a. Description (FO-6 and FO-9).

components, only the left brake will be described below.

NOTE

(The left brake components are illustrated in foldouts 6,

7 and 13).

The left reverse-range clutch (FO-6)

(2) The brake includes stationary cam

and the right reverse-range clutch

(35, FO-6), rotating apply cam (42), twelve steel balls

(FO-9) are identical.

Therefore,

(43), six external-tanged disks (4, FO-7), six internal-

description of one clutch will serve

splined disks (3), and apply disk (2) Brake hub (45, FO-

to describe the other.

The

6)is integral with the reverse range ring gear. Reaction

description below is keyed to foldout

plate assembly (5, FO-7) is the reaction member for the

6, the left reverse-range clutch.

brake clutch disks as well as the steer clutch disks.

Springs (13) and pins (15) also serve both the brake and

(1) The reverse-range clutch includes six

steer clutch.

internal-splined disks (33, FO-6), six external-tanged

(3) Brake apply components include shaft

disks (34), reaction disk (32), piston (3), retainer

(74, FO-13), cam (88), bearing (87), rollers (90), body

assembly (9), hub (19), eight pins (8), and twelve

assembly (79), and adjusting screw (40, FO-6)

springs (17).

Combined with the brake apply mechanism is brake

(2) Pins (8, FO-6) are held stationary at

signal valve (95, FO-13) and air valve assembly (76),

one end by recesses in the bevel gear housing and at

both of which are activated by lever (86).

the other end by recesses in the brake stationary cam.

b. Operation

These pins engage disks (34) and reaction disks (32)

(1) When the brake is applied, the vehicle

and prevent their rotation. Internal splined disks (33),

linkage causes brake apply shaft (74, FO-13) to rotate

positioned alternately between disks (34), engage hub

clockwise (right shaft rotates counterclockwise) Cam

(19). Piston (3) travels in a cavity, machined in the

(88) is splined to shaft (74) and is eccentric to it.

bevel gear housing.

Bearing (87), being mounted on and concentric with the

b. Operation. When the reverse-range clutch

cam, applies pressure on the end of adjusting screw (40,

is applied, hydraulic pressure behind piston (3, FO-6)

FO-6), installed in rotating apply cam (42). Thus, when

pushes the piston against reaction disk (32). The

apply shaft 74, FO-13) rotates, brake rotating apply cam

reaction disk compresses all twelve clutch disks against

(42), FO-6) moves in a clockwise direction, as viewed

brake apply stationary cam (35). This grips the internal-

from the left side.

splined disks and holds them stationary. These disks

(2) Rotating apply cam (42, FO-6) and

engage the splines on hub (19) and thus prevent its

rotation. This locks reverse-range planetary carrier (24)

2-5