TM 9--2520--215--34
0005 00--26
THEORY OF OPERATION -- CONTINUED
0005 00
TORQUE PATHS THROUGH TRANSMISSION – Continued
Torque Path In Neutral, Converter Drive, Right Steer
NOTE
Refer to Torque Path In Neutral, Converter Drive, No Steer and Hydraulic System, Neutral
Converter Drive Right Steer
Refer to Torque Path in Neutral, Converter Drive, No Steer for the explanation of conditions in neutral. The
explanations below are expanded to included steer action in neutral.
To obtain steer in neutral, the engine speed must be sufficient to cause rotation of the turbine (by converter
action). When the converter shaft rotates, the steer gear train rotates. Thus, counterclockwise rotation is imparted to
both right and left steer--clutch drive gears.
The right steer clutch is engaged, locking the right steer--planetary sun gear to the steer--clutch drive gear.
This causes the sun gear to rotate counterclockwise also.
An idler gear, in mesh with the right tie--shaft drive gear and tie--shaft pinion, rotates clockwise. This drives
the tie shaft counterclockwise. A pinion at the left end of the tie shaft, in mesh with the left tie--shaft drive gear, rotates
the left tie--shaft drive gear and left steer--planetary sun gear clockwise.
The right and left steer--planetary sun gears rotate in opposite directions instead of remaining stationary as
they do in straight travel. In neutral, the steer--planetary ring gears are stationary. They become reaction members
while the normally stationary sun gears become the driving members.
Since the right steer--planetary sun gear rotates counterclockwise, the carrier is also forced to rotate counter-
clockwise, within the stationary ring gear. This causes the transmission output to rotate counterclockwise, driving the
right vehicle track in reverse. The left output--steer sun gear rotates clockwise, causing the output rotation at the left
side to be clockwise. The left vehicle track is driven forward. The tendency of the right and left steer--planetary ring
gears to rotate is canceled. This happens because the gears are splined to the driven bevel gear shaft and their reac-
tions are in opposite directions.
In neutral steer, the vehicle will pivot around its center without forward or reverse movement.
Refer to this work package for the ratios involved in neutral steer.
Torque Path in Neutral, Converter Drive, No Steer---Schematic View
