Fourth Gear--Straight Travel

TM 9-2520-249-34&P

d. Fourth Gear--Straight Travel (fig. 2-18).

Figure 2-18. Fourth gear, straight travel operation-torque path.

(1) In fourth gear, the torque path to the

torque through the bevel-driven gear to the cross shaft

transmission outputs is the same as that described for

at a speed reduction of 1.444 to 1.

second gear (b, above), except that the high range

(2) In the output sections, the output

clutches are engaged and operate as explained in b (1),

clutch is engaged instead of the low-range clutch.

Engagement of the high-range clutch locks the turbine

above. Thus, there is direct drive from the turbine shaft

shaft to the intermediate-range planetary carrier. The

to the bevel drive gear, a 1.444 to 1 speed reduction in

intermediate-range sun gear is splined to the turbine

the bevel gears, direct from the bevel-driven gear to the

shaft. Thus, two elements of the intermediate-range

output shafts, and a 2.222 to 1 speed reduction in the

planetary are locked together and must rotate as a unit.

output reduction gears. The total mechanical speed

The inter connection of the intermediate-range planetary

reduction from the converter output shaft to the

with the low-range planetary causes the low-range

transmission outputs is 3.209 to 1. At output stall, the

planetary to rotate as a unit. The low-range planetary is

total torque ratio available (output-to-engine) is 2.6 x

splined to the bevel drive gear which transmits the

3.209) 8.343 to 1.

2-34