Remove Rotor Chaincases and Rotor Axle
a. remove spacer tube
b. remove rotor drive assembly
1. Securely block up the rotor axle and the rotor chaincases.
2. Unpin the rod end (1) of the rotor door lift cylinder, rotate the cylinder up out of the way, then reinstall the pin through the door clevis.
3. Attach a lifting device to the rotor door, raise the door, and install the door lock (2).
4. If working on an RR-250, unbolt and remove the rotor end rings (3) on the rotor drum.
Otherwise, unbolt and remove the end tools (4) on the rotor drum.
5. Unbolt and remove the seal housing shields (5) from each end of the rotor. If the retainer halves (6) stayed with the bearing housing (7), remove the retainer halves.
6. Unpin the push rods (8) from the chaincases (9). Rotate the push rods out of the way.
7. Unbolt and remove the chaincase covers (10) from one of the chaincases.
8. Locate the master link for the drive chain (11), then remove the link.
9. Unwrap the chain from around the sprockets.
10. Unbolt and remove the thrust plate (12), then slide the lower sprocket (13) and the wear sleeve (14) off the stub shaft (15).
11. Slide the upper sprocket and shaft assembly (16) outboard far enough to attach a lifting device to the assembly, then remove the assembly from the chaincase.
12. Unbolt the chaincase hub (17) from the chaincase.
13. Attach a lifting device to the chaincase, then move the chaincase straight out from the rotor assembly.
14. Repeat steps 7 through 13 for the other chaincase.
15. Attach a lifting device to the rotor axle and move the axle away.
Install Rotor Chaincases and Rotor Axle
1. Move the axle into position and securely block up the axle.
2. Move a chaincase into position on the rotor assembly and securely block up the chaincase.
3. Loosely install the mounting bolts that hold the chaincase hub (17) to the chaincase.
4. Position the retainer halves (6) on the bearing housing (7), position the housing shields (5), then loosely install the bolts for the seal housing shields.
5. Slide the wear sleeve (14) and the lower sprocket (13) onto the stub shaft (15), position the thrust plate (12) on the sprocket, then loosely install the mounting bolts.
6. Repeat steps 2 through 5 for the other chaincase.
7. Check that the chaincase hubs will mount flush with the chaincases and that the lower sprockets will mount flush with the oil seal housings. Adjust the position of the chaincases as necessary.
8. Alternately and evenly tighten the mounting bolts for each chaincase hub, each pair of seal housing shields, and each thrust plate.
9. Attach a lifting device to one upper sprocket and shaft assembly (16) and insert the shaft through the chaincase hub and into the axle. Repeat for the other sprocket and shaft assembly.
10. Wrap the chains (11) around the sprockets and install the master links.
11. Install the chaincase covers (10) and gaskets.
12. Pin the push rods (8) to the chaincases (9).
13. If working on an RR-250, install the rotor end rings (3) on the rotor drum.
Otherwise, install the end tools (4) on the rotor drum.
14. Rotate the rotor door cylinder down into position and pin the rod end (1) of the cylinder to the door.
15. Add lubricant as needed to both chaincases and the rotor axle.
a. install the rotor drive assembly
b. install spacer tube
Disassemble Rotor Axle
a. remove rotor chaincases and rotor axle
1. Place the axle in axle stands so it can be safely worked on.
2. Remove the axle drain plug and drain the lubricant from the axle.
3. Unbolt and remove the electric shift unit.
4. Remove nuts, capscrews and washers fastening carrier to axle housing. Remove differential carrier assembly.
NOTE: If the gear set is to be reused and since it is best to maintain an established wear pattern with used gears, check tooth contact pattern (see page 48, step 52) and ring gear backlash (see page 47, steps 48 through 50) before disassembling differential carrier.
5. Mount differential carrier assembly in repair stand. Loosen, but do not remove, the pinion nut.
6. Remove shift fork seal and spring.
7. Remove expansion plugs.
8. Working at the lower (or small) plug hole, drive out the shift fork shaft (1).
9. Remove sliding clutch (2).
NOTE: If the gear set is to be reused, punch mark the bearing adjusters and bearing caps (3) for location and easier adjustment during reassembly.
10. On tooth side of ring gear, cut the lockwire and remove the bearing capscrews.
11. Remove the cap, the adjuster and the lock.
12. On the back side of ring gear, cut the lockwire and remove the bearing capscrews.
13. Remove the bearing cap, bearing adjuster and the lock (3).
NOTE: If the gear set is to be reused, remove the bearing cap, the adjuster and the lock as an assembly. This will facilitate correct positioning of the ring gear during reassembly.
14. Remove the bearing cups.
15. Using a chain hoist, lift the ring gear and differential assembly (4) out of the carrier.
16. If necessary, invert the carrier in the stand, then remove pinion bearing cage capscrews. Invert the carrier to the original position.
During the following procedures, do not allow pinion to drop on hard surface.
17. Drive pinion cage assembly out of carrier.
NOTE: If the gear set is to be reused, keep the shim pack intact for use during reassembly. If the original shims cannot be reused, record the number of shims in the pack and the size of each.
18. Remove the pinion nut.
19. Remove the yoke from the pinion using a suitable puller.
20. Support the pinion cage (5) and press the pinion and pilot bearing out of the bearing cage.
21. Press oil seal and outer bearing cup (6) out of cage. Discard the oil seal.
22. Remove and retain the bearing spacer washer and bearing spacer from the pinion.
23. Using a bearing cup remover, remove the inner bearing cup (7) from the cage.
24. Using a split-type puller, mount the splitter vertically between the pilot bearing (8) and the pinion (9) then press the splitter between the bearing and the pinion.
25. Mount the pinion, pilot bearing, and splitter horizontally and press the pinion out of the bearing.
26. Move the ring gear and differential assembly to the work area.
27. Remove the nuts and bolts fastening the ring gear and support cases.
28. Remove the small support case (10) and thrust washer (11).
29. Remove the ring gear.
NOTE: A soft faced hammer or mallet may be required to dislodge gear from its mounting.
30. To remove the differential assembly, place the large support case and the assembly on a bench. Position the case on its side, then slowly roll the case and slide the differential assembly out of the case.
31. Remove the thrust washer (12) from the large support case (13).
32. Tilt the differential assembly to slide an idler pin (14) partially out of the assembly, then, being careful not to drop the pinion (15), remove the pin then remove the pinion.
33. Repeat step 32 for the other idler pins and pinions.
34. Punch mark (16) the differential cases for correct location during assembly.
35. Remove the capscrews (17) and separate the case halves.
36. Lift off the thrust washer (18) and the first side gear (19).
37. Lift out the spider (20), the side pinions (21) and the thrust washers (22).
38. Remove the second side gear (23) and thrust washer (24).
39. Attempt to remove the high speed clutch plate. If the clutch plate cannot be removed by hand, press off the plate as follows:
a. Insert properly sized adapters of round metal stock (25) into two of the idler pin holes and invert the case assembly in a press with the clutch plate (26) down. The length of the adapter should provide space for removal of the plate.
b. Use bar stock (27) to block the center hole in the clutch plate and press against it with the press ram.
c. Continue to press until the plate breaks loose from the plate dowel pins.
40. Remove the bearing cones from the support cases using a suitable puller.
NOTE: If a puller is not available, holes (28) are provided in the case to enable removal of bearing cone with a pilot punch. Tap alternately through each hole until the cone is removed.
Assemble Rotor Axle
NOTE: Lubricate internal parts with gear lubricant during assembly.
1. Press bearing cones on differential assembly support cases.
2. Position high speed clutch plate and the case in a press with the larger chamfered side of the clutch plate toward the case.
It is important that the ends of the dowel pins are recessed 3.18 mm (.125 in) below surface of the clutch plate. If pins extend beyond plate surface, press pins to proper depth.
3. Press the clutch plate on case.
4. Place thrust washer and side gear in the differential case half that has pins.
5. Assemble side pinions and thrust washers on spider. Place the assembly in the differential case.
6. Place side gear and thrust washer in position on side pinions.
7. Align punch marks (16) and place plain case on case that has pins.
8. Install capscrews (17) and tighten them to 122 - 149 Nm (90 - 110 lb ft).
NOTE: Turn side gear hub to check for free differential rotation. Rotation may require up to 65 Nm (50 ft lb) torque.
9. Install idler pins (14) and pinions (15).
10. Place thrust washer in large support case.
11. During installation of ring gear, temporarily use two bolts in mounting holes to assure bolt hole alignment. Place ring gear on large support case, then remove the two bolts.
12. Place support case and ring gear assembly upright on a bench or the floor. Carefully lower differential assembly into case. Engage idler pinions with ring gear teeth to complete the installation.
NOTE: During differential installation, be sure thrust washer stays in its proper mounting position.
13. Install thrust washer (11) and small support case (10) over differential assembly.
14. Carefully install ring gear bolts, making certain flat on bolt head is seated against the outside diameter of the large support case. Install and tighten the nuts to 149 to 176 Nm (110 to 130 lb ft).
15. Temporarily install the sliding clutch and check planetary for free rotation.
16. Before installing bearing cups, check for burrs on bearing surfaces and remove any found.
17. Press the inner bearing cup (7) in cage, then use a .03 mm (.001 in) feeler gauge to determine if the cup is fitted firmly in the cage. The feeler gauge should not be able to slip between the cup and the cage shoulder at any point on the shoulder circumference. Repeat for the outer bearing cup (6).
18. Press pilot bearing (8) on pinion.
19. Stake bearing using staking tool.
NOTE: Most axles will have a slip fit outer pinion bearing, but recent design changes on some models provide a press fit on this bearing. Procedures for adjusting both types of pinion bearing design are contained in the following steps.
20. Assemble the pinion cage (5), the cups (6, 7), the bearings cones (29, 30), the bearing spacer washer (31), and a 4.7 mm (.185 in) bearing spacer (32).
NOTE: During assembly procedure, center the bearing spacer and the spacer washer between the two bearing cones.
21. Lubricate the bearings and place the assembly in a press.
NOTE: Position the sleeve or spacer so that load is applied directly to the backface of the outer bearing cone.
22. Apply press load (33) of 162 800 to 171 600 N (37 000 to 39 000 lb) to the assembly.
NOTE: Use a calibrated load cell to insure proper loading.
23. Wrap a soft wire or strong string around the bearing cage, attach a spring scale (34) and pull steadily until the pinion bearing cage rotates. Note the spring scale reading. The preload is correct when spring scale reading is 15 to 30 N (3 to 7 lb).
24. If necessary, adjust pinion bearing preload by changing the pinion bearing spacer. A thicker spacer will decrease preload; a thinner spacer will increase preload.
25. Once correct bearing preload has been established, note the spacer size used. This should be the proper size for final assembly of axles with a slip fit outer pinion bearing.
NOTE: If the unit has a press fit outer pinion bearing, select a spacer that is .025 mm (.001 in) larger for use in final assembly. The larger spacer compensates for slight growth in the bearing which occurs when it is pressed on the pinion shank.
26. Remove the inner bearing cone from the cage, then, using a properly sized sleeve, press inner bearing cone (29) on pinion.
27. Install the bearing spacer and the bearing spacer washer on the pinion.
28. Place the outer pinion bearing cone (30) in the outer bearing cup of the bearing cage.
29. Using a properly sized sleeve to prevent distortion, carefully press the oil seal (35) into the pinion bearing cage.
30. Check the yoke (43) for nicks or grooves and remove any found. Lubricate the oil seal lip and yoke sealing surface.
31. Set the cage, bearing, and seal assembly on the pinion shank.
32. Position the yoke on the pinion splines. Be careful not to damage the seal or roll the outer dust lip under while installing the yoke.
33. For axles with a slip fit outer pinion bearing:
With the pinion bearings and yoke properly seated, but not loaded, hold the assembly and measure the oil seal drag using a spring scale as described in step 23. Record the reading.
34. For axles with a press fit outer pinion bearing:
Using a properly sized sleeve (36) contacting the washer face of the yoke, press the yoke and cage assembly on the pinion, being careful to leave enough free play in the bearings to allow approximately 1.59 mm (.063 in) vertical movement of the bearing cage. Measure the oil seal drag using a spring scale as described in step 23. Record the reading.
NOTE: When oil seal drag has been determined, the pinion bearing preload should be measured by using one of the following two methods: press method and vise method or vise method alone. If a press having a calibrated load cell to accurately indicate press load is available, the press method and then the vise method should be used. If such a press is not available, the vise method alone should be used.
35. Press method:
a. Position a properly sized sleeve (36) to clear the thread portion of the pinion and bear against the washer face of the yoke. Apply a press load of 158 400 to 167 200 N (36 000 to 38 000 lb) to preload the assembly.
b. While loaded, check the rolling resistance of the bearing cage and seal assembly with a spring scale (34) in the manner described in step 23. Note the scale reading.
c. Subtract the oil seal drag measured in step 33 or 34 from the value obtained above to determine the corrected spring scale reading. The correct spring scale reading should be 22 to 52 N (5 to 12 lb).
NOTE: If the value obtained does not fall within the acceptable range, disassemble the pinion and bearing cage assembly and change the spacer. A thicker spacer will result in less preload, a thinner spacer will provide more preload. Repeat the steps above until proper preload is obtained.
d. Recheck the rolling torque using the vise method described below.
36. Vise method:
a. Install pinion nut and tighten to 1139 to 1383 Nm (840 to 1020 lb ft).
b. Clamp the yoke in a vise allowing the bearing cage to rotate.
c. Check the rolling resistance of the bearing cage and seal assembly using a spring scale (34) as described in step 23. Note the scale reading.
d. Subtract oil seal drag measured in step 33 or 34 from the spring scale reading noted above. The corrected scale reading should be 22 to 52 N (5 to 12 lb).
NOTE: If the value obtained does not fall within the acceptable range given, disassemble the pinion and bearing cage assembly and change the spacer. A thicker spacer will result in less preload, a thinner spacer will provide more preload. Repeat the steps above until proper preload is obtained.
37. Place shim pack (37) on carrier and align the oil holes.
NOTE: If the gear set is to be reused, install same quantity and size of the shims removed during disassembly. If a new gear set is being used, install a nominal shim pack .61 mm (.024 in) in depth.
38. Install pinion assembly. Install bearing cage cap screws. Tighten the screws to 216 to 238 Nm (160 to 176 lb ft).
39. Place ring gear and differential assembly in carrier. Insure that ring gear and drive pinion mesh properly and that the support case pilot (38) rests in the bearing cap pedestal (39).
NOTE: During installation, tilt carrier to allow support case pilot to rest in carrier bore, then install bearing cup as shown. Also install bearing cup on opposite side of differential.
40. Install bearing adjusters and caps (3).
41. Install and tighten bearing cap screws finger tight.
42. Lubricate differential bearings (40).
43. Loosen the bearing adjuster (41) on the same side as the ring gear teeth until the first thread on the bearing adjuster is visible.
44. Tighten the bearing adjuster (42) on the backface side of the ring gear until there is no backlash.
NOTE: Backlash can be tested by facing toward the ring gear teeth and pushing the gear away from the body while gently rocking the gear from side to side. There should be no free movement.
45. Rotate the ring gear and check for any point where the gear may bind. If such a point exists, loosen and retighten the backface side adjuster.
46. Find the point of tightest mesh between the ring gear and pinion. Make all further adjustments from this point.
47. At teeth side of ring gear, tighten adjuster until it contacts the bearing cup. Continue tightening adjuster two notches. This will preload bearings and provide approximate backlash.
48. Position a dial indicator on a ring gear tooth, at the extreme heel end, perpendicular to the tooth surface.
49. Rotate the ring gear until it is in contact with a pinion gear tooth, then adjust the dial indicator to read 0.
50. Rotate the ring gear back and forth and note the indicator reading.
NOTE: The indicator reading for new gearing should be .20 to .46 mm (.008 to .018 in). If used gearing is being reinstalled, use the readings obtained during disassembly.
51. If the indicator reading noted in step 50 is not correct, add or remove backlash as required.
a. To remove backlash, loosen the adjuster (41) on the tooth side of the ring gear several notches. Tighten the opposite adjuster (42) one notch. Return to adjuster on tooth side of ring gear and tighten adjuster until it contacts the bearing cup. Continue tightening the same adjuster 2 or 3 notches. Recheck backlash.
b. To add backlash, loosen the adjuster (41) on the tooth side of the ring gear several notches. Loosen the opposite adjuster (42) one notch. Return to adjuster on tooth side of ring gear and tighten adjuster until it contacts the bearing cup. Continue tightening the same adjuster 2 or 3 notches. Recheck backlash.
NOTE: For new gearing, check ring gear backlash after each shim change and adjust if necessary.
52. Check the tooth contact pattern as follows:
a. Paint ring gear teeth with marking compound and roll the gear to obtain a contact pattern.
b. The length of the pattern for new gearing in an unloaded condition should be approximately one-half to two-thirds of the ring gear tooth.
c. Used gear sets should display the same contact pattern observed before disassembly. A correct pattern is up slightly off the toe and centers evenly along the face width between the top land and root. Otherwise, the length and shape of the pattern are highly variable and are considered acceptable as long as there is some pattern on toe end of the tooth.
53. If the contact pattern shows incorrect tooth depth contact, change drive pinion position by altering the shim pack under the cage and cup assembly. Used gears should achieve proper contact with the same shims removed from the axle at disassembly.
a. If the pattern is too close to the root of the gear tooth, add pinion shims.
b. If the pattern is too close to the top land of the gear tooth, remove pinion shims.
NOTE: Tooth contact patterns are a function of the relative positions of the ring gear and pinion. An improper pattern will require relocation of either or both. Always adjust pinion position first, if necessary, then ring gear position. Check ring gear backlash after each shim change and adjust if necessary to maintain correct backlash. Always recheck tooth contact pattern after making shim pack changes.
54. If the contact pattern shows incorrect face width contact, change backlash and recheck the contact pattern.
a. With the pattern concentrated at the toe (too far down the tooth), add backlash by loosening the bearing adjuster on the teeth side of ring gear several notches. Loosen the opposite adjuster one notch.
Return to adjuster on teeth side of ring gear and tighten adjuster until it contacts the bearing cup. Continue tightening the same adjuster 2 or 3 notches. Recheck backlash.
b. If the pattern is concentrated at the heel (too far up the tooth), remove backlash by loosening the bearing adjuster on the teeth side of ring gear several notches. Tighten the opposite adjuster one notch.
Return to adjuster on teeth side of ring gear and tighten adjuster until it contacts the bearing cup. Continue tightening the same adjuster 2 or 3 notches. Recheck backlash.
55. When preload, backlash, and tooth contact are correct, align differential bearing adjusters and locks, then tighten differential bearing cap screws to 501 to 583 Nm (370 to 430 lb ft).
56. Install adjuster lock and cap screw on ring gear teeth side.
57. On the backface side of the ring gear, install the adjuster lock, dowel bushings and cap screws. Tighten the cap screws to 216 to 238 Nm (160 to 176 lb ft).
58. Install lockwire on differential bearing cup, and adjuster lock cap screws.
59. Position shift fork in carrier opening, then install sliding clutch.
60. With clutch installed, engage shift fork yoke with clutch collar, then install shift fork shaft (1).
61. Install expansion plugs to seal openings.
62. Install shift unit seal and spring.
NOTE: Before installing carrier assembly, inspect and thoroughly clean interior of axle housing.
63. Use silicone rubber gasket compound on axle housing mating surface as shown. Gasket compound will normally set in 20 minutes. Install carrier before compound sets or compound will have to be reapplied.
64. Install differential carrier assembly in axle housing.
65. Install cap screws, nuts and lockwashers. Tighten to 298 to 325 Nm (220 to 240 lb ft).
a. install the rotor chaincases and rotor axle