Front Axle - C205F: Adjustments
ADJUSTMENTSRing gear and pinion are supplied as matched sets only. The identifying numbers for the ring gear and pinion are painted onto the pinion gear shaft and the side of the ring gear. A plus (+) number, minus (-) number or zero (0) along with the gear set sequence number (01 to 99) is on each gear. This first number is the amount (in thousandths of an inch) the depth varies from the standard depth setting of a pinion marked with a (0). The next two numbers are the sequence number of the gear set. The standard set-ting from the center line of the ring gear to the back face of the pinion is 99.690 mm (3.925 inch). The standard depth provides the best teeth contact pattern.
Compensation for pinion depth variance is achieved with select shims. The shims are placed between the rear pinion bearing cone and the pinion gear head. (Fig. 5).
If a new gear set is being installed, note the depth variance marked on both the original and replacement pinion. 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. Intersecting figure represents plus or minus amount needed.
Note the painted number on the shaft of the drive pinion (-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 a Pinion Gauge Set, Pinion Block 8177, Arbor Discs 8541 and Dial Indicator C-3339 (Fig. 6).
1. Assemble Pinion Height Block 6739, Pinion Block 8177 and rear pinion bearing onto Screw 6741 (Fig. 6).
2. Insert assembled height gauge components, rear bearing and screw into the housing through the pinion bearing cups (Fig. 7).
3. Install front pinion bearing and Cone 6740 onto the screw hand tight (Fig. 6).
4. Place Arbor Discs 8541 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.
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 the housing so dial probe and scooter block are flush against the surface of the pinion height block. Hold scooter block in place and zero the dial indicator. Tighten dial indicator face lock screw.
7. With scooter block still in position against the pinion height block, slowly slide the dial indicator probe over the edge of the pinion height block. Observe how many revolutions counterclockwise the dial pointer travels (approximately 0.125 inch) to the out-stop of the dial indicator.
8. Slide the dial indicator probe across the gap between the pinion height block and the arbor bar with the scooter block against the pinion height block (Fig. 9). When the dial probe contacts the arbor bar, the dial pointer will turn clockwise. Bring dial pointer back to zero against the arbor bar, do not turn dial face. Continue moving the dial probe to the crest of the arbor bar and record the highest reading. If the dial indicator can not achieve the zero reading, the rear bearing cup or the pinion depth gauge set is not installed correctly.
9. Select a shim equal to the dial indicator reading plus the drive pinion gear depth variance number marked on the shaft of the pinion gear using the opposite sign on the variance number. For example, if the depth variance is -2, add +0.002 inch to the dial indicator reading.
10. Remove the pinion depth gauge components from the housing
DIFFERENTIAL BEARING PRELOAD AND GEAR BACKLASH
Differential side bearing preload and gear backlash is achieved by selective shims inserted between the bearing cup and the housing. The proper shim thick-ness can be determined using slip-fit Dummy Bearings 8398 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 over-all shim thickness is the total of the dial indicator reading, starting point shim thicknesses, and the preload specification added together. The gear back-lash 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 side of the differential (Fig. 10).
SHIM SELECTION
NOTE: It is difficult to salvage the differential side bearings during the removal procedure. Install replacement bearings if necessary.
1. Remove side bearings from differential case.
2. Install ring gear, if necessary, on differential case and tighten bolts to specification.
3. Install Dummy Bearings 8398 on differential case.
4. Install differential case in the housing.
5. Insert Dummy Shims 8107 (0.118 inch (3.0 mm)) starting point shims between both dummy bearings and the housing (Fig. 11).
6. Install the marked bearing caps in their correct positions. Install and snug the bolts.
7. Using a dead-blow hammer to seat the differential dummy bearings to each side of the differential housing (Fig. 12) and (Fig. 13).
8. Thread Pilot Stud C-3288-B into rear cover bolt hole below ring gear (Fig. 14).
9. Attach Dial Indicator C-3339 to post and position dial indicator plunger on a flat surface on a ring gear bolt head (Fig. 14).
10. Push firmly and hold differential case to pinion side of axle housing (Fig. 15) and zero dial indicator.
11. Push firmly and hold differential case to the ring gear side and record dial indicator reading (Fig. 16).
12. Add the dial indicator reading to the starting point shim thicknesses to determine the total shim thickness necessary to achieve zero differential end play.
13. Add 0.2 mm (0.008 inch) to the zero end play total. This new total represents the thickness of shims necessary 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, dummy bearings, and starting point shims from the housing.
16. Install the pinion in the axle housing. Install the companion flange and establish the correct pinion rotating torque.
17. Install differential case and Dummy Bearings in axle housing with a single dummy shim on the ring gear side of the axle and tighten retaining cap bolts.
18. Position the dial indicator plunger on a flat surface between the ring gear bolt heads (Fig. 14).
19. Push and hold differential case toward pinion.
20. Zero dial indicator face to pointer.
21 Push and hold differential case to ring gear side of the housing.
22. Record dial indicator reading.
23. Subtract 0.05 mm (0.002 inch) from the dial indicator reading to compensate for backlash between ring and pinion gears. Add the resulting measurement to the thickness of the single starting point shim. This total is the thickness of shim required to achieve proper backlash.
24. Subtract the backlash shim thickness from the total preload shim thickness. The remainder is the shim thickness required on the pinion side of the axle housing.
25. Rotate dial indicator out of the way on pilot stud.
26. Remove differential case, dummy bearings and dummy shim from the housing.
27. Install new side bearing cones and cups on differential case.
28. Install Spreader W-129-B and Adapter Plates 8142-A on the housing and spread open enough to receive differential case.
29. Place the side bearing shims in the differential housing against the housing shoulder.
30. Install the differential case in the housing.
31. Rotate the differential case several times to seat the side bearings.
32. Position the indicator plunger against a ring gear tooth (Fig. 17).
33. Push and hold ring gear upward while not allowing the pinion gear to rotate.
34. Zero dial indicator face to pointer.
35. 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 inch) and 0.20 mm (0.008 inch). If backlash is not within specifications transfer the necessary amount of shim thick-ness from one side of the differential housing to the other (Fig. 18).
36. 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 the Gear Contact Pattern 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.
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 pat-tern.
3. With 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. 19) and adjust pinion depth and gear backlash as necessary.