John Deere stx38 - Manual (Page 187)

3/21/97
5 - 23
POWER TRAIN THEORY OF OPERATION
TRANSAXLE OPERATION
PEERLESS MODELS
915-012A/915-012B
STX30 (SN 135159—160758) &
STX38 (SN 139615—185586)
Function:
The transaxle transmits power from the engine,
through the belt traction drive system, into the
transaxle gear matrix, and out the drive axles to the
rear wheels. The transaxle provides a gear selection of
five forward speeds and one reverse speed.
It also provides the means to interrupt the flow of power
when shifted into neutral.
Major Components:
• Transaxle drive sheave
• Input shaft and pinion gear
• Beveled drive gear, drive shaft with small drive
chain sprocket, drive chain, and drive gears
• Intermediate shifter/brake shaft with shifter fork,
shift collar, shift keys, large drive chain sprocket/
reverse gear, drive chain, and transfer gears
• Idler shaft and combination gear
• Differential gears and axle shafts
• Wheels and tires.
Theory of Operation:
Forward:
The transaxle input sheave is keyed to the input pinion
(F). The input pinion (F) drives the bevel input gear (H).
The bevel input gear (H) rotates independently of the
shifter/brake shaft (A) but constantly rotates the drive
shaft (K) and gears (J). When a forward gear is
selected, the shift fork (N) moves the shift spool (O)
and shift fingers (L) in alignment with one of the driven
gears (I). The shift fingers (L) lock the selected driven
gear (J) to the driven shaft (P). Power is then
transmitted to the differential gear (E) and through the
spider gear (D) and axle gear (C) to the axles (G).
Reverse:
When reverse gear (B) is selected, power is
transmitted from the drive gears (J) and drive shaft (K),
through the reverse idler (M). The reverse idler (M)
changes the direction of rotation between the drive
gears (J) and the reverse gear (B), rotating the shifter/
brake shaft (A) in the opposite direction.
M42158
A
L
P
O
N
M
K J
H
I
F
G
E
D
C
B
G