TM-9-2520-246-34
TRANSMISSION MODEL 3052, NSN 2520-00-347-4520
TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT; MAINTENANCE MANUAL
MAY 1978
TM-9-2520-246-34 - Page 80 of 153
TM 9-2520-246-34
Section V. DESCRIPTION, OPERATION, AND DATA (MODEL T-136-21)
4-18. General.
This section provides repair
instructions for the sprag equipped transfer, model T-
136-21
4-19.
(See fig. 4-26 and 4-27.)
Description and Operation.
a. Description.
Sprag equipped transfer, model T-
136-21, is a 2-speed synchromesh unit driven from the
transmission by a propeller shaft. The transfer
distributes power to front and rear axles through the
propeller shafts. In addition to high and low speeds,
the transfer gearing is designed to drive the front axle
slightly slower than the rear axles and this difference
in speed is taken up by an overrunning sprag unit on
the front output shaft during normal operation. When
the rear wheels lose traction, the sprag unit
automatically engages, causing the front wheels to
drive the vehicle also. The handbrake drum is
mounted on the transfer-rear-output-shaft companion
flange. (See fig. 4-27.)
which moves the synchronizer into contact with the
input shaft low-speed gear or the input shaft high-
speed gear. Power is distributed to all three axles,
although the overrunning sprag units allow the front
wheels to turn freely until the rear wheels lose
traction, at which time the front wheels are engaged
drive also.
(1) Low Range.
When the transfer is shifted to
low range, the synchronizer assembly is moved
forward on the input shaft to engage the input shaft
low-speed gear which is in mesh with the idler shaft
low-speed gear. Because the low-speed gear is keyed
the idler shaft, the power flow is through the idler
shaft gears, to the rear and front output shaft and
shaft gears, and to the companion flanges.
(2) High Range.
When the transfer is shifted into
high range, the synchronizer assembly is moved
rearward on the input shaft to engage the input shaft
high-speed gear which is in mesh with the idler shaft
high-speed gear. Because the high-speed gear is keyed
to the idler shaft, power flow is through the idler shaft
gears to the rear and front output shaft and gears.
b. Operation.
The selection of high or low range in
the transfer is accomplished by a shifting mechanism,
in
to
Figure 4-26. Sprag Quipped Transfer Model T-136-21 — Front View.
4-19
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