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Home/Chevrolet/Silverado 3500 HD/Chevrolet Silverado 3500 HD (2007-2012)/Repair manual/Differentials & Drive Axles/Front Drive Axle: Adjustments
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Front Drive Axle: Adjustments Chevrolet Silverado 3500 HD

Differentials & Drive Axles ~1804 words

Adjustment Procedure

  1. Install the inner axle bearing and the inner axle seal, if necessary. Refer to «Front Drive Axle Inner Shaft Seal and Inner Shaft Bearing Replacement»(ref-317243-S06255134002009060900000) .
  2. Install the following components into the inner axle shaft housing: Install the inner axle shaft (1) into the inner axle shaft housing (4). Install the thrust washer (with tabs) (5). Ensure the tabs on the thrust washer are aligned with the slots in the inner shaft housing. Install the thrust washer (without tabs) (6). Install the retaining ring (7) into the inner axle shaft (1).
  3. Install the inner axle shaft housing into a vise. Clamp only on the mounting flange of the inner axle shaft housing.
  4. Push on the inner end of the inner axle shaft and move the shaft outboard as far as it will go.
  5. Install the J 34673 (1) and the J 34672 (2) onto the inner shaft housing as shown. See «Special Tools»(ref-317243-S25031904232009060900000) .
  6. Using the J 34672 , measure the distance from the edge of the inner axle shaft to the surface of the J 34673 . See «Special Tools»(ref-317243-S25031904232009060900000) . Ensure the base of the J 34672 is flat against the inner axle shaft.
  7. Using the J 34672 , measure the distance from the machined surface of the differential carrier housing to the outer surface of the front drive axle clutch shaft. See «Special Tools»(ref-317243-S25031904232009060900000) .
  8. Subtract the measurement obtained in step 6 from the measurement obtained in step 7. This measurement is the distance between the inner axle shaft and the clutch shaft before subtracting the J 34673 . See «Special Tools»(ref-317243-S25031904232009060900000) .
  9. Using a micrometer, measure the thickness of the J 34673 . See «Special Tools»(ref-317243-S25031904232009060900000) .
  10. Subtract the thickness of the J 34673 , measured in step 9, from the measurement determined in step 8. See «Special Tools»(ref-317243-S25031904232009060900000) . This is the shim thickness for the front axle without having any axle shaft endplay.
  11. The correct shim size will be one size smaller than the figure obtained in the previous step. Note the following examples: If the figure obtained in step 8 was 3.53 mm (0.139 in), use a 3.30 mm (0.130 in) shim. If the figure obtained in step 8 was 3.30 mm (0.130 in), use a 3.05 mm (0.120 in) shim.

Alternate Adjustment Method

  1. Install the original shim to the shaft. Use the chassis grease in order to hold the shim in place.
  2. Install the inner axle housing assembly to the differential carrier case. Do not use sealer at this time.
  3. Install the bolts and tighten to 40 N.m (30 lb ft).
  4. Measure the shaft end play using the following procedure: Install the J 8001 or the equivalent on the axle tube end. The plunger of the indicator must be at a right angle to the axle flange. Move the shaft back and forth and read the end play. The correct end play is 0.03-0.51 mm (0.001-0.020 in). If the end play is incorrect, install a thicker or thinner shim as needed in order to bring the end play into the specified range.
  1. Install the pinion bearing cups into the differential carrier assembly. Refer to «Front Differential Drive Pinion Gear Bearing Cup Installation (8.25 Inch Axle w/J 45858)»(ref-317243-S13526106092009060900000) , «Front Differential Drive Pinion Gear Bearing Cup Installation (8.25/9.25 Inch Axles w/J 36598)»(ref-317243-S26665623602009060900000) or «Front Differential Drive Pinion Gear Bearing Cup Installation (9.25 Inch Axle w/J 45754)»(ref-317243-S11896172072009060900000) .
  2. Before assembly, lubricate the pinion bearings with axle lubricant. Use the correct fluid. Refer to «Adhesives, Fluids, Lubricants, and Sealers»(ref-317243-S27784450652009060900000) .
  3. Install the J 36601-4 or the J 36601-3 (4) to the J 36601-7 (1).
  4. Install the J 21777-35 for the 8.25 inch axle or the J 21777-8 for the 9.25 inch axle (3) to the J 36601-7 (1).
  5. Install the inner pinion bearing into the differential carrier case half.
  6. Insert the J 36601-7 (1) with the J 21777-35 or the J 21777-8 (3) through the inner pinion bearing and the differential carrier case half.
  7. Install the outer pinion bearing.
  8. While holding the outer pinion bearing in position, install the J 36601-5 (2), the washer, and the nut to the J 36601-7 (1).
  9. While holding the J 36601-7 (1) stationary with a wrench, tighten the nut on the J 36601-7 (1). Tighten: Tighten the nut until all of the end play is removed from the J 36601 . See «Special Tools»(ref-317243-S25031904232009060900000) .
  10. Rotate the assembly several times in both directions in order to seat the pinion bearings.
  11. While holding the J 36601-4 or the J 36601-3 (4) stationary, measure the rotating torque of the J 36601 using an inch-pound torque wrench. See «Special Tools»(ref-317243-S25031904232009060900000) . Specification: The rotating torque of the J 36601 should be between 1.1-2.3 N.m (10-20 lb in).
  12. If the torque is less than 1.0 N.m (10 lb in), continue to tighten the nut on the J 36601-7 until a rotating torque of 1.1-2.3 N.m (10-20 lb in) is obtained.
  13. Install the adjustment screw and the lock nut of the J 29763 (2) to the J 36601-4 or the J 36601-3. See «Special Tools»(ref-317243-S25031904232009060900000) .
  14. Install the J 29763 to the adjustment screw and lock nut assembly. See «Special Tools»(ref-317243-S25031904232009060900000) . Tighten the lock nut to hold the J 29763 in place.
  15. Place the contact pad of the J 36601-4 or to the J 36601-3 into the differential side bearing bore.
  16. Adjust the J 29763 to the differential bearing bore by doing the following: See «Special Tools»(ref-317243-S25031904232009060900000) . Loosen the lock nut on the J 29763 . See «Special Tools»(ref-317243-S25031904232009060900000) . Place the contact pad of the J 36601-4 or the J 36601-3 onto the differential side bearing bore. With the contact pad of the J 36601-4 or the J 36601-3 touching the differential side bearing bore, push down on the J 29763 until the needle of the J 29763 has turned 3/4 of a turn clockwise. See «Special Tools»(ref-317243-S25031904232009060900000) . Tighten the lock nut of the J 29763 . See «Special Tools»(ref-317243-S25031904232009060900000) .
  17. Rotate the J 36601-4 or the J 36601-3 (1) back and forth until the needle of the J 29763 (2) indicates the lowest point in the differential side bearing bore. See «Special Tools»(ref-317243-S25031904232009060900000) .
  18. At the lowest point of deflection, move the housing of the J 29763 until the needle indicates ZERO. See «Special Tools»(ref-317243-S25031904232009060900000) .
  19. Move the J 36601-4 or the J 36601-3 back and forth again to verify the zero setting. Adjust the housing of the J 29763 as necessary to set the needle to ZERO. See «Special Tools»(ref-317243-S25031904232009060900000) .
  20. After the ZERO setting is obtained and verified, grasp the J 36601-4 or the J 36601-3 (1) by the flats and move the J 36601-4 or the J 36601-3 out of the differential side bearing bore.
  21. The value indicated on the J 29763 (2) is the thickness of the shim needed in order to set the depth of the pinion. See «Special Tools»(ref-317243-S25031904232009060900000) .
  22. Select the shim that indicates the correct thickness. Measure the shim with a micrometer in order to verify that the thickness is correct.
  23. Remove the pinion depth setting tools.
  24. Remove the pinion bearings.
  25. Install the pinion shim between the drive pinion and the inner pinion bearing and assemble the differential carrier. Refer to «Differential Carrier Assembly Assemble (9.25 Inch Axle)»(ref-317243-S42179180122009060900000) or «Differential Carrier Assembly Assemble (8.25 Inch Axle Lock Ring Style)»(ref-317243-S26722693132009060900000) .

Differential pinion gear shims are available in the following sizes

8.25 Inch Axle9.25 Inch Axle
0.508 mm (0.020 in)0.5131 mm (0.0202 in)
0.533 mm (0.021 in)0.5395 mm (0.0212 in)
0.559 mm (0.022 in)0.5639 mm (0.0222 in)
0.584 mm (0.023 in)0.5893 mm (0.0232 in)
0.610 mm (0.024 in)0.6147 mm (0.0242 in)
0.635 mm (0.025 in)0.6401 mm (0.0252 in)
0.660 mm (0.026 in)0.6655 mm (0.0262 in)
0.686 mm (0.027 in)0.6909 mm (0.0272 in)
0.711 mm (0.028 in)0.7163 mm (0.0282 in)
0.737 mm (0.029 in)0.7417 mm (0.0292 in)
0.762 mm (0.030 in)0.7671 mm (0.0302 in)
0.787 mm (0.031 in)0.7925 mm (0.0312 in)
0.813 mm (0.032 in)0.8179 mm (0.0322 in)
0.838 mm (0.033 in)0.8433 mm (0.0332 in)
0.864 mm (0.034 in)0.8687 mm (0.0342 in)
0.889 mm (0.035 in)0.8941 mm (0.0352 in)
0.914 mm (0.036 in)0.9195 mm (0.0362 in)
0.940 mm (0.037 in)0.9449 mm (0.0372 in)
0.965 mm (0.038 in)
0.991 mm (0.039 in)
1.016 mm (0.040 in)
1.041 mm (0.041 in)
1.067 mm (0.042 in)
1.092 mm (0.043 in)
1.118 mm (0.044 in)
1.143 mm (0.045 in)
1.168 mm (0.046 in)
1.194 mm (0.047 in)
1.219 mm (0.048 in)
1.245 mm (0.049 in)
1.270 mm (0.050 in)

Shim Sizes

Inspection & Adjustment Procedure

  1. Remove all alignment marks made previously and re-mark the location of the differential adjuster nut sleeves in relation to the differential carrier assembly case halves. Ensure that the notches can be counted when turned.
  2. Install the J 8001-1 (1, 2), the J 8001-2 (3), and the J 8001-3 (4) as shown. Ensure that the button contacts the outer edge of the pinion yoke and that the plunger is at a right angle to the pinion yoke.
  3. Move the pinion yoke back and forth through the pinion yoke's free play while not allowing the ring gear to move.
  4. Record the dial indicator reading.
  5. To determine the actual backlash, divide the dial indicator reading by 2. An actual dial indicator reading of 0.16 mm (0.006 in) means that there is actually 0.08 mm (0.003 in) backlash. Specification: The backlash between the ring gear and the drive pinion should be between 0.08-0.25 mm (0.003-0.010 in) with a preferred specification of 0.13-0.18 mm (0.005-0.007 in).
  6. If the backlash is too small, increase the backlash by turning the right differential adjuster nut sleeve out one notch using the J 36599-A , 8.25 inch axle, or the J 36615 , 9.25 inch axle, and the left differential adjuster nut sleeve in one notch using the J 36599-A until the correct backlash is obtained. See «Special Tools»(ref-317243-S25031904232009060900000) .
  7. If the backlash is too large, decrease the backlash by turning the left differential adjuster nut sleeve out one notch using the J 36599-A and the right differential adjuster nut sleeve in one notch using the J 36599-A , 8.25 inch axle, or the J 36615 , 9.25 inch axle, until the correct backlash is obtained.
  8. Recheck the rotating torque of the pinion and differential assembly and adjust, if necessary. Refer to «Differential Carrier Assembly Assemble (9.25 Inch Axle)»(ref-317243-S42179180122009060900000) or «Differential Carrier Assembly Assemble (8.25 Inch Axle Lock Ring Style)»(ref-317243-S26722693132009060900000) .
  9. Once the backlash and bearing preload is within specifications, remove the alignment markings and place new alignment marks between the differential bearing adjuster nut and the differential carrier assembly case.
  10. Continue the assembly of the differential carrier. Refer to «Differential Carrier Assembly Assemble (9.25 Inch Axle)»(ref-317243-S42179180122009060900000) or «Differential Carrier Assembly Assemble (8.25 Inch Axle Lock Ring Style)»(ref-317243-S26722693132009060900000) .

Adjustments Affecting Tooth Contact

The following 2 adjustments affect the tooth contact pattern

  1. Backlash adjustment
  2. Pinion depth adjustment

The effects of bearing preloads are not readily apparent on hand-loaded tooth contact pattern tests. However, bearing preloads should be within specifications before proceeding with backlash and pinion depth adjustments.

Pinion Depth Adjustment

Adjust the position of the pinion by increasing or decreasing the distance between the pinion head and the centerline of the ring gear. Decreasing the distance moves the pinion closer to the centerline of the ring gear. Increasing the distance moves the pinion farther away from the centerline of the ring gear.

Backlash Adjustment

Adjust the backlash by means of moving the side bearing adjuster sleeves which move the case and ring gear assembly closer to or farther from the pinion. Also use the adjuster sleeves in order to set the side bearing preload.

  1. If the left side adjuster sleeve is moved in, along with an equal outward movement of the right side adjuster, the backlash will increase.
  2. If the left side adjuster sleeve is moved out, along with an equal inward movement of the right side adjuster, the backlash will decrease.

More articles — Front Drive Axle