3-64. TRACTION MOTOR ASSEMBLY (cont)
i. Use iron blue pigment and check the tooth marking of the hypoid gear by rotating the gears back and forth
over several teeth. A contact marking located slightly off center, toward the small end of the tooth, is desired.
j. If gear tooth marking is not as shown, and is a cross bearing (toward small end of the tooth on one side and
large end on the other side), check for possible cause as follows:
(1) Check mounting dimension of hypoid pinion.
(2) Check backlash of hypoid gears.
(3) Check mounting surface gear box for damage such as high spots.
(4) Check motor frame mounting surface in the same manner.
k. After the hypoid pinion is adjusted to the proper mounting dimension and the tooth marking is satisfactory,
add an 0.008-inch (0.203 mm) shim to shim pack (55) to correct for thermal expansion of the armature shaft.
l. Check that armature end play is between 0.002 and 0.004 inch.
72. Refer to paragraph 3-63 for installation of traction motor-gear unit to wheelaxle unit.
73. Remove 1-inch eye bolt (4). Position hypoid oil pan (3) in gear unit (8) and install three lockwashers (2) and
capscrews (1). Lockwire capscrews.