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Pinion Depth & Bearing Preload

  1. 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.
  2. 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. Use a suitable 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.
  3. If new pinion and ring gear assembly are to be installed, proceed as follows: Determine pinion depth adjustment figure (See Fig 1) of old and new pinions and find shim adjustment figure from chart. Adjust original shim pack accordingly and proceed as in step  2.
  4. Remove pinion flange and nut, and remove front pinion bearing cone. Install original preload shim pack. Lubricate and install bearing cone. Install pinion flange and nut, and tighten to specifications while rotating pinion shaft. Place housing in position so that pinion shaft is vertical pointing up. Using an INCH lb. torque wrench, rotate shaft through several revolutions to measure rotating torque. Check measurements against pinion bearing preload in specifications. To decrease preload, add shims; to increase preload, subtract shims. After adjustment is made, install oil seal and recheck pinion depth.
    NOTE: Ignore torque needed to start shaft rotating.
    Fig 1: Pinion and Ring Gear Markings Showing Pinion Depth Adjustment Figure
    G09330748Courtesy of NOT AVAILABLE
  5. Front axles only: Check seals in axle housing bores. If condition is questionable, replace using suitable installer tool. See Fig 2.
    NOTE: When installing front axle shaft, be sure that seals are not dislodged.
    Fig 2: Correct Procedure for Installing Inner Oil Seals
    G09330749Courtesy of NOT AVAILABLE
PINION DEPTH SHIM ADJUSTMENT CHART (INCHES)

Old Pinion New Pinion
-4 -3 -2 -1 0 +1 +2 +3 +4
+4 +0.008 +0.007 +0.006 +0.005 +0.004 +0.003 +0.002 +0.001 0
+3 +0.007 +0.006 +0.005 +0.004 +0.003 +0.002 +0.001 0 -0.001
+2 +0.006 +0.005 +0.004 +0.003 +0.002 +0.001 0 -0.001 -0.002
+1 +0.005 +0.004 +0.003 +0.002 +0.001 0 -0.001 -0.002 -0.003
0 +0.004 +0.003 +0.002 +0.001 0 -0.001 -0.002 -0.003 -0.004
-1 +0.003 +0.002 +0.001 0 -0.001 -0.002 -0.003 -0.004 -0.005
-2 +0.002 +0.001 0 -0.001 -0.002 -0.003 -0.004 -0.005 -0.006
-3 +0.001 0 -0.001 -0.002 -0.003 -0.004 -0.005 -0.006 -0.007
-4 0 -0.001 -0.002 -0.003 -0.004 -0.005 -0.006 -0.007 -0.008
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