Pinion Depth & Bearing Preload

Pinion is adjusted by shims placed between inner bearing cup and housing, and by shims placed between pinion shaft shoulder and outer bearing.
Shims behind inner bearing cup adjust position of pinion in relation to ring gear. Shims behind outer bearing adjust pinion inner and outer bearing preload.
If old pinion and ring gear assembly are used, proceed as follows: Install original shims and inner bearing cup. Install outer bearing cup. Press bearing cone onto pinion shaft and install shaft into housing.
Install outer bearing cone, companion flange, and nut. DO NOT install outer shims or seal at this time. Tighten nut to obtain bearing preload of 10-30 ft. lbs. (14-41 N.m).
Use a gauge to measure distance from ring gear center to machined button on end of pinion gear. Add or subtract shims from under inner bearing cup to obtain nominal dimension listed in specifications.
If new pinion and ring gear assembly are to be installed, proceed as follows: Determine pinion depth adjustment figure of old and new pinions and find shim adjustment figure from chart. Adjust original shim pack accordingly and proceed as in step 3).
NOTE: An oil slinger between inner bearing cone and pinion, and a baffle, between inner bearing cup and carrier, have been added to front axle assemblies.
Remove pinion gear, rear bearing cup, and starter shim. Install pinion depth shim of correct thickness in housing bearing cup bore. Reinstall rear bearing cup.
Install pinion bearing, oil slinger, yoke, washer, and old pinion nut. Tighten nut to specifications, while rotating pinion shaft. Position housing so that pinion shaft is in vertical position (pointing up).
With INCH lb. torque wrench, rotate shaft through several revolutions to measure rotating torque. Check measurement against pinion bearing preload in specifications. To decrease preload, add shims; to increase preload, subtract shims.
NOTE: Ignore torque needed to start shaft rotating.

Fig 1: Pinion Gear Markings Showing Depth Adjustment Figure

NOTE: Ring gear and pinion numbers must match.
After adjustment is made, install oil seal and recheck pinion depth. Check seals in front axle housing bores. If condition is questionable, replace using installer tool.

NOTE: When installing front axle shafts be sure that seals are not dislodged.