TM 5-3810-300-24 & P2
6. Check Hypoid Gear Backlash.
If original gears are reused the backlash should be
made the same as before disassembly. For new gears
the new backlash should be from .006" to .012". Adjust
backlash by moving the gear only. This is done. by
backing off one adjusting ring and advancing the
opposite ring the same amount.
7. Check Tooth Contact.
Apply oiled red lead lightly to the hypoid gear teeth.
When the pinion is rotated, the red lead is squeezed
away by the contact of the teeth, leaving bare areas the
exact size, shape and location of the contacts.
Sharper impressions may be obtained by applying a small amount of resistance to the gear with a flat steel bar and using
a wrench to rotate the pinion. When making adjustments, check the drive side of the gear teeth. Coast side should be
automatically correct when the drive side is correct. As a rule, coating about twelve teeth is sufficient for checking
With adjustments properly made (pinion at correct depth
and backlash set at .010") the above contacts will be
procured. The area of contact favors the toe and is
centered between the top and bottom of the tooth.
The hand rolled pattern shown at left (gears unloaded),
will result in a pattern centered in the length of the tooth
when the gears are under load, shown at right. The
loaded pattern will be almost full length and the top of
pattern will approach the top of the gear tooth
SATISFACTORY TOOTH CONTACT.