Front Axle - 216FBI

ADJUSTMENTS





Ring and pinion gears are supplied as matched sets only. The identifying numbers for the ring and pinion gear are etched into the face of each gear (Fig. 1). A plus (+) number, minus (-) number or zero (0) is etched into the face of the pinion gear. This number is the amount (in thousandths of an in.) the depth varies from the standard depth setting of a pinion etched with a (0). The standard depth provides the best gear tooth contact pattern.





Compensation for pinion depth variance is achieved with a select shim/oil slinger. The shims are placed between the rear pinion bearing and the pinion gear head (Fig. 2).

If a new gear set is being installed, note the depth variance etched into both the original and replacement pinion. Add or subtract this number from the thickness of the original depth shim/oil slinger to compensate for the difference in the depth variances. Refer to the Depth Variance chart.

Note where Old and New Pinion Marking columns intersect. Intersecting figure represents plus or minus the amount needed. Note the etched number on the face of the pinion gear head (-1, -2, 0, +1, +2, etc.). The numbers represent thousands of an inch deviation from the standard. If the number is negative, add that value to the required thickness of the depth shims. If the number is positive, subtract that value from the thickness of the depth shim. If the number is 0 no change is necessary.





PINION GEAR DEPTH VARIANCE

PINION DEPTH MEASUREMENT AND ADJUSTMENT





Measurements are taken with pinion bearing cups and pinion bearings installed in the housing. Take measurements with Pinion Gauge Set and Dial Indicator C-3339 (Fig. 3).
1. Assemble Pinion Height Block 6739, Pinion Block 6734 and rear pinion bearing onto Screw 6741 (Fig. 3).





2. Insert assembled height gauge components, rear bearing and screw into the housing through pinion bearing cups (Fig. 4).
3. Install front pinion bearing and Cone-nut 6740 hand tight.





4. Place Arbor Disc 6732 on Arbor D-115-3 in position in the housing side bearing cradles (Fig. 5).

NOTE: Arbor Discs 6732 has different step diameters to fit other axles. Choose proper step for axle being serviced.

5. Install differential bearing caps on arbor discs and install bearing cap bolts. Tighten bearing cap bolts to 108 Nm (80 ft. lbs.).
6. Assemble Dial Indicator C-3339 into Scooter Block D-115-2 and secure set screw.
7. Position Scooter Block/Dial Indicator flush on the pinion height block. Hold scooter block and zero the dial indicator.





8. Slowly slide the scooter block across the pinion height block over to the arbor (Fig. 6). Move the scooter block till dial indicator crests the arbor, then record the highest reading.
9. Select a shim/oil slinger equal to the dial indicator reading plus the pinion depth variance number etched in the face of the pinion (Fig. 1). For example, if the depth variance is -2, add +0.002 in. to the dial indicator reading.

PRELOAD SHIM SELECTION





Differential side bearing preload and gear backlash is achieved by selective shims positioned between the differential side bearing cups and the housing. The proper shim thickness is determined using slip-fit Dummy Bearings D-345 in place of the differential side bearings and a Dial Indicator C-3339. Before proceeding with the differential bearing preload and gear backlash measurements, measure the pinion gear depth and prepare the pinion for installation. Establishing proper pinion gear depth is essential to establishing gear backlash and tooth contact patterns. After the overall shim thickness to take up differential side play is measured, the pinion is installed, and the gear backlash shim thickness is measured. The overall shim thickness is the total of the dial indicator reading and the preload specification added together. The gear backlash measurement determines the thickness of the shim used on the ring gear side of the differential case. Subtract the gear backlash shim thickness from the total overall shim thickness and select that amount for the pinion gear side of the differential (Fig. 7). Differential shim measurements are performed with spreader W-129-B removed.

NOTE: It is difficult to salvage the differential side bearings during the removal procedure. Install replacement bearings if necessary.

1. Remove differential side bearings from differential case.
2. Remove factory installed shims from differential case.
3. Install ring gear on differential case and tighten bolts to specification.
4. Install dummy side bearings D-345 on differential case.
5. Install differential case in the housing.





6. Install the marked bearing caps in their correct positions and snug the bolts (Fig. 8).








7. With a dead-blow hammer, seat the differential dummy bearings to each side of the housing (Fig. 9) and (Fig. 10).





8. Thread Pilot Stud C-3288-B into rear cover bolt hole below ring gear (Fig. 11).
9. Attach the Dial Indicator C-3339 to pilot stud. Position the dial indicator plunger on a flat surface between the ring gear bolt heads (Fig. 11).





10. Push and hold differential case to pinion gear side of the housing and zero dial indicator (Fig. 12).





11. Push and hold differential case to ring gear side of the housing and record dial indicator reading (Fig. 13).
12. Add 0.25 mm (0.010 in.) to the zero end play total. This total represents the thickness of shims needed to preload the new bearings when the differential is installed.
13. Rotate dial indicator out of the way on the pilot stud.
14. Remove differential case and dummy bearings from the housing.
15. Install the pinion gear in the housing. Install the pinion yoke and establish the correct pinion rotating torque.
16. Install differential case and dummy bearings D-345 in the housing (without shims), install bearing caps and tighten bolts snug.
17. Seat ring gear side dummy bearing (Fig. 10).
18. Position the dial indicator plunger on a flat surface between the ring gear bolt heads (Fig. 11).





19. Push and hold differential case toward pinion gear and zero dial indicator (Fig. 14).





20. Push and hold differential case to ring gear side of the housing and record dial indicator reading (Fig. 15). Subtract 0.05 mm (0.002 in.) from this reading. This is the shim thickness for the ring gear side.

NOTE: This is the shim needed on the ring gear side for proper backlash.

21. Subtract the backlash shim thickness from the total preload shim thickness. The remainder is the shim thickness required on the pinion side of the housing.
22. Rotate dial indicator out of the way on pilot stud.
23. Remove differential case and dummy bearings from the housing.
24. Install the selected shims onto the differential case hubs.
25. Install side bearings on differential case hubs with Install C-3716-A and Handle C-4171.
26. Install bearing cups on differential.
27. Install Spreader W-129-B and some items from Adapter Set 6987 on the housing and spread open enough to receive differential case.

CAUTION: Do not spread housing over 0.38 mm (0.015 in.). The housing can be damaged if overspread.

28. Install differential case into the housing.
29. Remove spreader from the housing.
30. Rotate the differential case several times to seat the side bearings.





31. Position the indicator plunger against a ring gear tooth (Fig. 16).
32. Push and hold ring gear upward while not allowing the pinion gear to rotate.
33. Zero dial indicator face to pointer.





34. Push and hold ring gear downward while not allowing the pinion gear to rotate. Dial indicator reading should be between 0.12 mm (0.005 in.) and 0.20 mm (0.008 in.). If backlash is not within specifications transfer the necessary amount of shim thickness from one side of the housing to the other (Fig. 17).
35. Verify differential case and ring gear runout by measuring ring to pinion gear backlash at eight locations around the ring gear. Readings should not vary more than 0.05 mm (0.002 in.). If readings vary more than specified, the ring gear or the differential case is defective. After the proper backlash is achieved, perform Gear Contact Pattern Analysis procedure.

GEAR CONTACT PATTERN
The ring and pinion gear contact patterns will show if the pinion depth is correct. It will also show if the ring gear backlash has been adjusted correctly. The backlash can be adjusted within specifications to achieve desired tooth contact patterns.
1. Apply a thin coat of hydrated ferric oxide or equivalent to the drive and coast side of the ring gear teeth.
2. Wrap, twist and hold a shop towel around the pinion yoke to increase the turning resistance of the pinion. This will provide a more distinct contact pattern.





3. With a boxed end wrench on the ring gear bolt, rotate the differential case one complete revolution in both directions while a load is being applied from shop towel. The areas on the ring gear teeth with the greatest degree of contact against the pinion teeth will squeegee the compound to the areas with the least amount of contact. Note and compare patterns on the ring gear teeth to Gear Tooth Contact Patterns chart (Fig. 18) and adjust pinion depth and gear backlash as necessary.