TM 55-2210-224-34
3-64. TRACTION MOTOR ASSEMBLY (cont)
INSTALLATION (cont)
h. Relocate hypoid pinion (11) by the following:
(1) Remove capscrews (51) and lockwashers (52). Remove bearing housing (53) and shim pack (55). Install
bearing housing.
(2) Place hypoid-pinion mounting gage in position. Move armature to obtain the proper mounting dimension;
allow for the plus or minus variation in mounting dimension of the particular pinion.
(3) Use a feeler gage and check and record the dimension between the motor frame and bearing housing (53).
Install a shim pack (55) of that thickness. Install lockwashers (52) and capscrews (51).
(4) Recheck mounting distance.
(5) Below is an example of a relocation:
(a) The nominal mounting dimension to the center line of intermediate shaft for the hypoid pinion is 5.464
inches (138.785 mm). The clearance between the mounting distance gage and the hypoid pinion is
0.030 inch (0.762 mm) plus or minus the dimension marked on the end of the pinion.
(b) The illustration shows a hypoid pinion having plus 16 correction (0.016 inch, or 0.4064 mm), which
means that the distance between the gage and the pinion (X dimension) must be set to 0.046 inch
(1.1684 mm) for proper mounting of the pinion.
(c) The actual mounting dimension in this case is 5.464 plus 0.016, or 5.480 inches (138.785 plus 0.4064
mm, or 139.192 mm).
(d) Adjustment should be held to within plus
or minus 0.001 inch (0.0254 mm) of actual value.
(6) After pinion has been set to proper mounting dimension, check the backlash of the hypoid gears with an
indicator. The proper backlash is etched on the hypoid ring gear as shown. The backlash is obtained by
shimming the intermediate shaft in the gear box. Set the indicator the value marked on the hypoid gear (for
new gears only). Where worn hypoid gears are assembled, the backlash must be measured before
disassembly, and the used gear should be adjusted to this value at assembly. Measure backlash as follows:
(a) Mount an indicator as shown, so that the pointer rests against the tooth face on the hypoid ring gear.
(b) Use a bar and force the intermediate shaft over to fully engage the hypoid gear and pinion and take up
the end play of the intermediate shaft.
(c) While holding the motor armature shaft rigid, rock the ring gear back and forth and measure the backlash
on the dial indicator.
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