4.9.2.1 2.1 Checking Yoke Runout
Mount a dial indicator to the transmission or axle housing as shown in
Figure 8-60
and
Figure 8-61
. If the yoke is the half round type, place the tip of the indicator measuring
plunger onto the machined surface of the yoke shoulder. If the yoke is the full round
type, pop a bearing cup out just enough to insert the indicator plunger onto the cup as
shown in
Figure 8-61
. Take the measurement, and then rotate the yoke 180 degrees
and measure again. If runout exceeds 0.005 inch, the yoke should be replaced. Note
that the reason for a yoke damaged in this manner is usually mechanic abuse caused
by aggressive separation of a Y-joint.
Figure 8-60 - When checking
half-round end yoke for runout,
place the indicator plunger on
smooth surface of shoulder.
4.9.2.2 Checking yoke vertical alignment
Figure 8-61 -
When checking a
full-round end yoke for runout,
be sure to leave enough surface
for the indicator plunger.
The machined shoulder of a half-round yoke or yoke bores in a full-round yoke should
be exactly 90 degrees to the centerline of the shaft to which the yoke is attached. If the
shaft is horizontal (0 degrees), the yoke should be vertical (90 degrees); if the shaft
angles away from a true horizontal plane, the yoke should be at an angle equal to 90
degrees minus the inclination of the shaft.
Before checking vertical alignment, make sure the vehicle is on a level surface. The
engine and transmission mounts should be secure. Also check the yoke for looseness
and tighten to specification if required.
When measuring the alignment of a yoke attached to the main transmission, first
disconnect the driveshaft from the end yoke. Next, put the transmission in neutral and
rotate the transmission output shaft until the yoke lugs are positioned vertically one
above the other. Then, if the yoke is a half-round type, place a protractor with a
magnetic base in a vertical position across the mechanical surfaces of the yoke (
Figure
8-62
). The protractor dial should read 90 degrees minus the inclination of the
engine/transmission plane.
NAVEDTRA 14050A
8-68