Rear Axle - 216RBI
ADJUSTMENTSRING AND PINION GEAR
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. 5). 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 inch) the depth varies from the standard depth setting of a pinion etched with a (0). The standard depth provides the best teeth contact pattern.
Compensation for pinion depth variance is achieved with select shims. The shims are placed under the inner pinion bearing on the pinion shaft.
If a new gear set is being installed, note the depth variance etched into both the original and replacement pinion gear. Add or subtract the thickness of the original depth shims to compensate for the difference in the depth variances. Refer to the Depth Variance charts.
Note where Old and New Pinion Marking columns intersect. The intersecting figure represents plus or minus the amount needed.
Note the etched number on the face of the drive pinion gear (-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 shim(s). If the number is positive, subtract that value from the thickness of the depth shim(s). If the number is 0 no change is necessary. Refer to the Pinion Gear Depth Variance Chart.
PINION GEAR DEPTH VARIANCE
PINION DEPTH MEASUREMENT AND ADJUSTMENT
Measurements are taken with pinion cups and pinion bearings installed in housing. Take measurements with Pinion Gauge Set 6730 and Dial Indicator C-3339 (Fig. 6).
1. Assemble Pinion Height Block 6739, Pinion Block 6734 and rear pinion bearing onto Screw 6741 (Fig. 6).
2. Insert assembled height gauge components, rear bearing and screw into axle housing through pinion bearing cups (Fig. 7).
3. Install front pinion bearing and Cone 6740 hand tight.
4. Place Arbor Disc 6732 on Arbor D-115-3 in position in the housing side bearing cradles (Fig. 8). Install differential bearing caps on Arbor Discs and tighten cap bolts to 41 Nm (30 ft. lbs.).
NOTE: Arbor Discs 6732 have different step diameters to fit other axle sizes. Pick correct size step for axle being serviced.
5. Assemble Dial Indicator C-3339 into Scooter Block D-115-2 and secure set screw.
6. Place Scooter Block/Dial Indicator in position in axle housing so dial probe and scooter block are flush against the rearward surface of the pinion height block. Hold scooter block in place and zero the dial indicator face to the pointer. Tighten dial indicator face lock screw.
7. Slowly slide the Scooter Block/Dial Indicator across the pinion height block over to the arbor bar (Fig. 9). Move the Scooter Block/Dial Indicator to the crest of the arbor bar and record the highest reading.
8. Select a shim equal to the thickest dial indicator reading plus or minus the drive pinion gear depth variance number etched in the face of the pinion gear (Fig. 5).
9. Remove the pinion depth gauge components from the axle housing.
PRELOAD SHIM SELECTION
Differential side bearing preload and gear backlash is achieved by selective shims inserted between the bearing cups and the housing. The proper shim thickness can be 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 gear 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 gear 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. 10).
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 axle housing (Fig. 11).
6. Install the marked bearing caps in their correct positions. Install and snug the bolts (Fig. 12).
7. Using a dead-blow hammer seat the differential dummy bearings to each side of the housing (Fig. 13) and (Fig. 14).
8. Thread Pilot Stud C-3288-B into rear cover bolt hole below ring gear (Fig. 15).
9. Attach a dial indicator C-3339 to Pilot Stud C-3288-B. Position the dial indicator plunger on a flat surface between the ring gear bolt heads (Fig. 15).
10. Push and hold differential case to pinion gear side of the housing and zero dial indicator (Fig. 16).
11. Push and hold differential case to ring gear side of the housing and record dial indicator reading (Fig. 17).
12. Add dial indicator reading to the starting point shim thickness. This is the total shim thickness to achieve zero differential end play.
13. Add 0.254 mm (0.010 inch) to the zero end play total. This new total represents the thickness of shims to compress, or preload the new bearings when the differential is installed.
14. Rotate dial indicator out of the way on pilot stud.
15. Remove differential case and dummy bearings from the housing.
16. Install pinion gear in the housing. Install the pinion yoke and establish the correct pinion rotating torque.
17. Install differential case and dummy bearings D-345 in the housing (without shims), install bearing caps and tighten bolts snug.
18. Seat ring gear side dummy bearing (Fig. 14).
19. Position the dial indicator plunger on a flat surface between the ring gear bolt heads. (Fig. 15).
20. Push and hold differential case toward the pinion gear and zero dial indicator (Fig. 18).
21. Push and hold differential case to ring gear side of the housing and record dial indicator reading (Fig. 19).
22. Subtract 0.05 mm (0.002 inch) from the dial indicator reading to compensate for backlash between ring and pinion gears. This total is the thickness shim required to achieve proper backlash.
23. 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.
24. Rotate dial indicator out of the way on pilot stud.
25. Remove differential case and dummy bearings from the housing.
26. Install side bearing shims on differential case hubs.
27. Install new side bearing cones and cups on differential case.
28. Install spreader W-129-B on the housing and spread axle opening enough to receive differential case.
29. Install differential case in the housing.
30. Install differential bearing caps loosely.
31. Remove spreader from the housing.
32. Tighten bearing caps bolts to 108 Nm (80 ft. lbs.).
33. Rotate the differential case several times to seat the side bearings.
34. Position the indicator plunger against a ring gear tooth (Fig. 20).
35. Push and hold ring gear upward while not allowing the pinion gear to rotate and zero dial indicator.
36. Push and hold ring gear downward while not allowing the pinion gear to rotate. Dial indicator reading should be between 0.12 mm - 0.20 mm (0.005 inch - 0.008 inch). If backlash is not within specifications transfer the necessary amount of shim thickness from one side of the housing to the other (Fig. 21).
37. 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 inch). 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 gear and pinion teeth contact patterns will show if the pinion depth is correct in the housing. 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.
The TOP LAND of the gear tooth is the top surface of the tooth. The PROFILE of the gear tooth is the depth of the tooth. The TOE of the gear is the portion of the tooth surface at the end towards the center. The HEEL of the gear is the portion of the tooth at the outer-end. The ROOT of the gear tooth is the lowest portion of the tooth (Fig. 22).
NOTE: If the PROFILE across the tooth is the same it is a 3 Axis cut gear. If the PROFILE across the tooth is tapered it is a 2 Axis cut gear.
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. Using a boxed end wrench on a 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. 23) and (Fig. 24) and adjust pinion depth and gear backlash as necessary.