GMC 1989 Light Duty Truck Repair Manual page 168

9 2
4B3-6 V -INCH RING GEAR
12. Set the dial indicator at zero. Push the indicator
down on the indicator shaft until the needle rotates
approximately of a turn to the right. Tighten the
3U
dial indicator in this postion (figure 13).
13. Rotate the gage shaft slowly back and forth until the
dial indicator reads the greatest deflection (when the
indicator needle is centered between movement to
the left and to the right).
14. At the point of greatest deflection, set the dial
indicator to zero. Repeat the rocking action of the
gage shaft to verify the zero setting.
A. Dial in d ic a to r and a rb o r p o s itio n e d on th e gage b lo c k .
M e a s u re m e n t a fte r th e a rb o r is m oved o ff o f th e gage b lo c k .
B.
15. Rotate the gage shaft until the dial indicator rod
does not touch the gage block.
16. Record the actual number on the dial indicator and
not the number which represents how far the needle
travels. This is the nominal pinion setting.
EXAMPLE: If the indicator needle moved to the left
1.70 mm (0.067-inch) to a dial reading of 0.84 mm
(0.033-inch) as shown in figure 13, record the dial
reading of 0.84 mm (0.033-inch) not 1.70 mm
(0.067-inch).
17. Check the pinion face for a pinion adjustment mark.
This mark indicates the best running position for the
pinion from the nominal setting.
18. Remove bearing caps (10) and depth gaging tools.
19. Install the correct pinion shim (
according to this procedure.
Figure 13— C hecking Pinion D epth
• If the pinion is stamped with a plus number,
add that many thousandths to the nominal
setting. If the nominal setting is 0.033-inch and
the pinion is marked +
depth would be 0.033-inch + 0.002-inch =
0.035-inch.
• If the pinion is stamped with a minus number,
subtract that many th ou san d ths from the
nom inal setting. If the nom inal setting is
0.033-inch and the pinion is marked -2, the
correct shim depth would be 0.033-inch -
0.002-inch = 0.031-inch.
• If the pinion has no plus or minus marked on
the pinion, use the nominal pinion setting to
select a shim.
1
2 , the correct shim
6 ) to the pinion
F-04682