M325B Material Handler Power Train Caterpillar

Assembly Procedure

1. Clean all parts and inspect all parts. If any parts are worn or damaged, use new parts for replacement.
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   Illustration 1	g00720337

2. Use Tool (A) and a suitable press in order to assemble the following components for the drive pinion:

   • drive pinion (1)

   • bearing (2)

   • bearings (3)

   • flange cover (4)
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   Illustration 2	g00724506

3. Use Tool (B) to install retaining clip (5) onto drive pinion (1).
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   Illustration 3	g00720367

4. Perform the following procedure in order to adjust the preload of the pinion bearings:

   1. Apply the correct amount of pressure to the pinion bearings. This pressure must be sustained. Refer to Table 2 for information on the required pressure.
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      Table 2

      Information for the Bearing Preload
      Pinion Shaft Thread Size	Required Pressure	Required Torque
      7/8"-20	9979 kg (20000 lb)	320 ± 47 N·m (235 ± 35 lb ft)
      1"-20	13608 kg (30000 lb)	475 ± 68 N·m (350 ± 50 lb ft)
      1 1/4"-12	24494 kg (54000 lb)	1085 ± 136 N·m (800 ± 100 lb ft)
      1 1/4"-18	24494 kg (54000 lb)	1085 ± 136 N·m (800 ± 100 lb ft)
      1 1/2"-12	24494 kg (54000 lb)	1288 ± 203 N·m (950 ± 150 lb ft)
      1 1/2"-18	24494 kg (54000 lb)	1288 ± 203 N·m (950 ± 150 lb ft)
      1 3/4"-12	22680 kg (50000 lb)	1424 ± 203 N·m (1050 ± 150 lb ft)
      2"-12	22680 kg (50000 lb)	1830 ± 203 N·m (1350 ± 150 lb ft)

   2. Attach a cord (6) to flange cover (4). Wind the cord around the flange cover several times.

      Note: Do not relieve pressure from the pinion bearings. Maintain pressure on the pinion bearings.

   3. Attach Tool (C) to the cord (6). Pull Tool (C) in order to obtain a value.

   4. Record the value that is indicated on Tool (C) from Step 4c. This value is the rolling torque.
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      Table 3

      Specifications for Pinion Bearing
      New Pinion Bearing	0.56 to 5.08 N·m (5 to 45 lb in)
      Used Pinion Bearing	1.13 to 3.39 N·m (10 to 30 lb in)

   5. Refer to Table 3 for the specifications for the pinion bearings. If the preload is not within specifications perform the following procedure.

      • Install a thinner bearing spacer in order to increase the preload of the pinion bearing.

      • Install a thicker bearing spacer in order to decrease the preload of the pinion bearing.

   6. Perform Steps 4a through Steps 4e until the bearing preload is correct.
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   Illustration 4	g00720375

5. Once the bearing preload is obtained, install the following items into differential carrier assembly (8): seal flange (4), pinion gear assembly and shims (9) (not shown). Install bolts (7) that secure the seal flange to the differential carrier assembly. Tighten the bolts to a torque of 129 ± 27 N·m (95 ± 20 lb ft).
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   Illustration 5	g00724442

6. Install yoke (11). Thread nut (10) onto the pinion shaft.

7. Use Tool (D) to hold yoke (11) while nut (10) is tightened. Use Tool (E) in order to tighten the nut to the following torque of 950 ± 136 N·m (700 ± 100 lb ft).

8. Perform the following procedure in order to assemble the differential assembly:
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   Illustration 6	g00724433

   1. Press the bearings (12) onto the differential case half (13).

   2. Repeat Step 8a in order to install the bearing onto the other differential case half.
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      Illustration 7	g00720383

   3. Press ring gear (15) onto differential case half (13) with a suitable press.

      Note: Ensure that the bolt holes in the differential case half are aligned with the bolt holes in the ring gear.

   4. Install bolts (14) that secure ring gear (15) to differential case half (13). Tighten the bolts to a torque of 130 ± 27 N·m (95 ± 20 lb ft).
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      Illustration 8	g00720391

   5. Turn over differential case half (13) and install thrust washer (16) (not shown) in differential case half. Then install side gear (17) into the differential case half.
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      Illustration 9	g00720398

   6. Install spider gear assembly (18) in differential case half (13).
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      Illustration 10	g00720399

   7. Install side gear (19) and thrust washer (20) onto spider gear assembly.
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      Illustration 11	g00720404

   8. Assemble differential case halves (13).

      Note: Ensure that identification marks (21) are aligned.

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      Illustration 12	g00720417

   9. Install sixteen bolts (22). Tighten the bolts in a number sequence to a torque of 136 ± 20 N·m (100 ± 15 lb ft).
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   Illustration 13	g00720415

9. Position carrier assembly (8) on Tooling (G). Use Tool (F) and a hoist in order to position differential (23) on the carrier assembly.

   Note: After the differential is installed, position the bearing cups on the differential bearings.

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   Illustration 14	g00720422

10. Install two caps (26) and adjusting ring (25) on differential carrier assembly (7).

    Note: Ensure that alignment marks (27) are aligned.

    Note: Ensure that the threads on the following items are aligned:adjusting ring, bearing cap and differential case assembly.

11. Install four bolts (24) that secure the bearing cap to the differential carrier assembly. Tighten the four bolts to a torque of 420 ± 54 N·m (310 ± 40 lb ft).

12. Apply the following preload to the differential bearings:

    Preload for the differential bearings ... 1.7 to 3.9 N·m (15 to 35 lb in)

13. Use the following adjustment procedure in order to adjust the preload of the differential bearings.
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    Illustration 15	g00720454

    1. Install Tool (H) on differential case assembly (8) in order to check for end play. Position Tool (H) against the back of ring gear (15).
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       Illustration 16	g00720457

    2. Loosen adjusting ring (25) that is opposite ring gear (15). A small amount of free play should be indicated by Tool (H). Move the ring gear to left (Y) and to right (Z) with a pry bar while Tool (H) is observed.

       Note: The pry bars must not touch the differential bearings.

    3. Tighten the adjusting ring that is opposite the ring gear so that no end play shows on the dial indicator.

    4. The adjusting ring is tightened one full notch from the zero end play that was recorded in Step 13c.
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    Illustration 17	g00720454

14. Use the following adjustment procedure in order to check for ring gear runout.

    1. Install Tool (H) on differential case assembly (8) in order to check for ring gear runout.

    2. Position Tool (H) against the back of ring gear (15). Then zero Tool (H).

    3. Rotate the ring gear in order to obtain a value on Tool (H).

    4. Record the value that is indicated on Tool (H) from Step 14c. This value is the ring gear runout.

    5. The ring gear runout must not exceed the following specification:

       Ring Gear Runout ... 0.200 mm (0.008 inch)

       If the ring gear runout exceeds the specification, remove the differential assembly from the differential carrier assembly. Refer to Disassembly And Assembly, "Differential - Disassembly".

    6. Inspect the components of the differential and inspect the differential carrier assembly for any problem that would cause the ring gear runout to exceed the specifications. Then repair the suspect components or replace the suspect components.

    7. After the components have been repaired or the components have been replaced, install the differential into the differential carrier assembly. Then perform Steps 12 through 14.
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    Illustration 18	g00724594

15. Use the following adjustment procedure in order to adjust the ring gear backlash.

    If the former gear set is installed, adjust the backlash to the value that was recorded during disassembly of the Differential.

    If a new gear set is installed, adjust the backlash to the specification for a new gear set.

    1. Refer to the following table for the specifications that are required.
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       Table 4

       Specifications For The Ring Gear Backlash
       Ring Gear Diameter	Backlash Setting
       	Range	New Gears
       Less than 431.8 mm (17.0 inch)	0.200 to 0.460 mm (0.008 to 0.018 inch)	0.30 mm (0.012 inch)
       Greater than 431.8 mm (17.0 inch)	0.250 to 0.510 mm (0.010 to 0.020 inch)	0.380 mm (0.015 inch)

    2. Install Tool (H) on differential case assembly (8) in order to check for ring gear backlash.

    3. Position Tool (H) so that the plunger is against the tooth surface of the ring gear (15). Then zero Tool (H).

    4. Hold the drive pinion in position. Rotate the ring gear against the drive pinion in order to obtain a value on Tool (H).

       Note: Do not allow the pinion gear to rotate.

    5. Record the value that is indicated on Tool (H) from Step 15d. This value is the ring gear backlash.

    6. Compare the measurement that was recorded in Step 15e to the specifications that are listed in Table 4. If the measurement is not within the specifications, perform Step 16 and Step 17. If the measurement is within the specifications, then skip Steps 16 and 17.

       Note: Backlash is increased by moving the ring gear away from the drive pinion. Backlash is decreased by moving the ring gear toward the drive pinion.

16. One adjusting ring is loosened one full notch. The opposite adjusting ring is tightened one full notch.

    Note: When you adjust the backlash, move the ring gear ONLY. DO NOT move the drive pinion.

17. Repeat Steps 15c through 16 until the backlash is within the specifications.

18. Check the tooth contact between the ring gear and the drive pinion gear after all of the adjustments have been made. Perform the following procedure in order to check the tooth contact.

    1. Ensure that the ring gear backlash is within specifications. Refer to Step 15 for this procedure.

    2. Use a small amount of Prussian blue, red lead, or paint on approximately twelve ring gear teeth. Rotate the ring gear so that the twelve marked teeth are next to the pinion gear.

    3. Rotate the ring gear forward and backward. The twelve ring gear teeth must go past the pinion gear six times in order to obtain a good contact pattern.

    4. Compare the contact pattern.

       When the differential carrier assembly is operated, a good contact pattern is approximately the entire length of the gear tooth. The top of the pattern will be near the top of the ring gear tooth.

       The location of a good hand rolled contact pattern for a used gear set must match the wear pattern in the ring gear. The area of the contact pattern will be smaller than the wear pattern.

       Proceed to Step 19 to adjust the contact pattern. If the contact pattern is correct, proceed to Step 18e.

       Note: A high contact pattern indicates that the pinion gear was not installed far enough into the differential carrier assembly. A low contact pattern indicates that the pinion gear was installed too far into the differential carrier assembly.

    5. Remove the pinion gear and the seal flange from the differential carrier assembly.

    6. To correct a high contact pattern, decrease the thickness of the shim pack under the seal flange. This will cause the pinion gear to move toward the ring gear.

       To correct a low contact pattern, increase the thickness of the shim pack under the seal flange. This will cause the pinion gear to move toward the ring gear.

    7. Install the pinion gear, the seal flange, and the shims into the differential carrier assembly.

    8. Repeat Steps 18b through 18h until the proper contact pattern is obtained.

       Note: Several adjustments of the pinion gear and the ring gear may be needed in order to obtain the correct contact pattern. The adjustment of the ring gear backlash should be correct before the tooth contact is checked.

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    Illustration 19	g00720469

19. Install cotter pin (28) that secures the retaining ring in position.

    Note: The component that secures the retaining ring can be one of the following items:cotter pin, lock plate and roll pin

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    Illustration 20	g00720476

20. Perform the following procedure in order to adjust the thrust screw:

    Note: If the differential carrier assembly does not have a thrust block, start at Step 20d.

    1. Rotate the differential carrier assembly in the repair stand until the back surface of the ring gear is toward the top.

    2. Place the thrust block on the back surface of the ring gear. The thrust block must be in the center between the outer diameter of the ring gear and the differential housing.

    3. Rotate the ring gear until the thrust block and the hole for the thrust screw in the differential carrier assembly are aligned.

    4. Install jam nut (29) on thrust screw (30) halfway between the ends.

    5. Thread the thrust screw into differential carrier assembly (8) until the screw stops against the ring gear or the thrust block (if equipped).

    6. Loosen the thrust screw by one-half turn.

    7. Tighten the jam nut to a torque of 230 ± 27 N·m (170 ± 20 lb ft).

End By:

1. Install the differential. Refer to Disassembly and Assembly, "Differential - Install".