Reverse-1 Gear, Straight Travel Operation

TM 9-2520-249-34&P

2-39.

Reverse-1 Gear, Straight Travel Operation (fig. 2-7)

Figure 2- 7. Hydraulic system, reverse-1 gear ,straight travel operation-schematic view.

a. Operational Circuits. This driving condition

(1) The manual selector valve directs

main pressure oil through the R-1 signal circuit to the

uses the same circuitry as forward, second gear, straight

top of the main-pressure regulator valve. The oil enters

travel, except that the reverse clutches are engaged, the

the valve body above the regulator valve and causes

reverse-signal circuits are charged, and the drive relay

the regulator valve to move downward. Thus, main

valve is upward.

pressure is regulated at a lower pressure because the

b. Manual Selector Valve.

The valve is

return spring must balance a greater opposing force.

moved toward the left until the retaining ball rests in the

reverse-1 (R-1) detent. This allows main-pressure oil

(2) Main pressure is lowered in this

(upper passage to charge the low-range clutch and the

driving condition to limit the torque through the driving

reverse signal circuits. The intermediate and high-range

clutches. If full torque were to be directed through this

clutches are simultaneously exhausted through ports in

gear combination it could be detrimental to the

the manual selector valve (lower passage) which

transmission components.

indexes with the clutch circuits.

c. Reverse-1 Signal Circuit.

2-21