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 100 of 153
TM 9-2520-246-34
CHAPTER 5
REPAIR OF POWER TAKEOFFS
Section I. DESCRIPTION, OPERATIONAL AND DATA (MODEL WN-7-28)
5-1. General.
This chapter contains the rebuild
instructions for power takeoff models WN-7-28,
WND-7-28, and P-136-C.
5-2. Description (Figure 5-1).
Heavy-duty power
takeoff model WN-7-28, is designed for mounting on
an SAE standard 6-hole or 6-stud power takeoff
opening. The unit is designed to be mounted on the
left or right side of the driving mechanism. The shifter
shaft extends through each end of the case so that the
shifting control linkage may be attached at either end.
The output shaft extends from the front of the case
and is provided with a woodruff key for mounting the
winch propeller shaft companion flange. Boots are
installed over the ends of the shifter shaft to protect
the surface of the shaft. The input gear of the power
takeoff is a cluster composed of a helical gear which is
constantly in mesh with the helical gear of the
transmission reverse idler gear, and the driving gear
which is of spur tooth construction. The power
takeoff has two speeds forward, neutral, and one
speed in reverse. A shifting mechanism provides for
selection of the desired speed and direction of rotation
of the output shaft. The shifting mechanism in neutral
position disengages the output shaft gears from the
driving gear.
5-3. Operation.
NOTE
The reference letters in parentheses pertain
to figure 5-2.
a. Input Gear.
The helical input gear (P) is in
constant mesh with the helical gear of the
transmission reverse-idler gear and therefore, is in
constant rotation when the transmission is engaged.
(Refer to transmission, Chapter 3.) The input gear (P)
is installed on a nonrotating input gearshaft (L) and is
mounted on the input gear roller bearings (N). The
shaft is pressed into the housing and secured with a
cotter pin. A thrust washer (M) is located at each end
of the input gear. The helical tooth portion of the
input gear (P) is in constant mesh with the reverse
gear (FF) which is installed on the reverse gearshaft
(JJ) and secured with the reverse gear pin (EE). The
reverse gearshaft rotates in two supporting bearings
(GG and FF).
b. Output Shaft.
The output shaft (H) is supported
in the housing on two ball bearings (F and S). Two
gears are installed on the output shaft (H). One is the
output shaft sliding gear (AA) which is moved
forward and backward on the shaft by the shifter fork
(Z). The other is the output shaft high speed gear (BB)
which is free on the output shaft (H) and is in
constant mesh with the input gear (P). The sliding
gear (AA) is splined to the output shaft (H) and may
be meshed with the spur teeth of the reverse gear
(FF), with the spur teeth of the input gear (P) (for low
speed operation) or may act as a clutch gear to couple
the output shaft high speed gear (BB) to the output
shaft (H).
c. Shifter Fork.
The shifter fork (Z) is attached to
the shifter shaft (A) by a capscrew. The fork engages
the circumferential groove on the sliding gear (AA).
Figure 5-1. Power Takeoff Model WN-7-28.
5-4. Data.
National stock number . . . . . . . . . . 252040-7061137
Ordnance number . . . . . . . . . . . . . . . . . . . . . . . 7061137
Manufacturer . . . . . . . . . . .
Spicer Div. - Dana Corp.
Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . WN-7-28
Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Heavy-duty
Speeds . . . . . . . . . . . . . . . . . . . . . . 2 forward, 1 reverse
Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transmission
Input gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Helical
Output shaft . . . . . . . . . . . . . . . . . 1¼ in. dia;5/16 in.
keyway
Bearings:
Output shaft . . . . . . . . . . . . . . . . . . . Two-ball type
Input shaft . . . . . . . . . . . . . . . . . . . . Two-roller type
Reverse gear . . . . . . . . . . . . . . . . . . Two-roller type
Horsepower delivered:
100 rpm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7
500 rpm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1000 rpm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Gear pitch
. . . . . . . . . . . . . . . . . . . . . . .
. . . . . . .
7/9 in.
Backlash (allowable) . . . . . . . . . . . . . . . . . . . . 0.008 in.
5-1
Back to Top
