- Articulated Truck
- 735C (S/N: LFJ1-UP; TFJ1-UP)
- 740 EJECTOR (S/N: 3F71-275; 3T71-175)
- 740 GC (S/N: 3F81-55; 3T81-47)
- 740C EJECTOR (S/N: LFN1-UP; TFN1-UP)
- 745 (S/N: 3F61-1142; 3T61-1193)
- 745C (S/N: LFK1-UP; TFK1-UP)
- 740 EJECTOR (S/N: 3F71-275; 3T71-175)
Reference: Disassembly and Assembly, UENR4227, "735C, 740C EJECTOR, and 745C Articulated Trucks Power Train"
Reference: Disassembly and Assembly, M0082513, "740 EJ and 745 Articulated Trucks Power Train"
Reference: Information Release Memo, PEGJ0075, "Cat® Henkel Loctite® Crossover Document"
Description Of Change:
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| Illustration 1 | g06292123 |
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Differential lock clutch assembly (A) Dowel (B) Thrust Ring (C) Differential Plate (D) Differential Case Assembly | |
The differential lock clutch on Articulated Trucks is now available with a new threaded dowel design. The newer dowel (A) and differential plate (C) are threaded which improves the durability of the differential case assembly (D). Dowel (A) is stronger and more resistant to breakage. Differential plate (C) is more resistant to dowel hole distortion.
Adaptable To: The following changes are adaptable to the machines within the listed serial numbers, and are effective with all machines after the listed serial numbers.
| Parts List | ||||
|---|---|---|---|---|
| Item | Qty | New Part Number | Part Name | Former Part Number |
| A | 3 | Dowel- Special | ||
| C | 1 | Differential Case - Reaction Plate(1) | ||
| D | 1 | Differential Case Assembly(2) | ||
| (1) | Included within |
| (2) | If replacing the differential case, use this part for the entire differential case assembly replacement. Otherwise there is an optional rework procedure for existing parts. |
Rework Procedure
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Do not operate or work on this product unless you have read and understood the instruction and warnings in the relevant Operation and Maintenance Manuals and relevant service literature. Failure to follow the instructions or heed the warnings could result in injury or death. Proper care is your responsibility. |
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| Illustration 2 | g06292107 |
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Differential lock clutch assembly (A) (B) (C) | |
| Parts List | |||
|---|---|---|---|
| Qty | Part Number | Part Name | Description |
| 1 | Differential Case Assembly | Differential Case Assembly(1) | |
| 1 | Differential Case - Reaction Plate | Differential Plate (2) | |
| 3 | Dowel - Special | Threaded Dowel | |
| 1 | Retaining Compound | LOCTITE 620 | |
| 3 | O-Ring Seal | Dowel Assembly O-Ring | |
| 1 | O-Ring Seal | Transfer Gear Gp O-ring Seal (Center Axle) | |
| 1 | O-Ring Seal | Pinion Gp O-Ring Seal (Rear/Front Axle) | |
| 1 | D-Ring Seal | Clutch Piston Seal | |
| 1 | D-Ring Seal | Clutch Piston Seal | |
| 28 or 21 | Bolt | Differential Gp Mounting Hex Bolts(3) | |
| (1) | Not needed if reworking differential plate (C) |
| (2) | Contained within |
| (3) | The quantity is 28 for front and rear assemblies and 21 for center assemblies. |
The differential lock clutch assembly reworked consists of updating the existing dowels (A) and the differential plate (C). There are two options for reworking the differential plate (C).
- Replacing the differential case assembly (D) (includes updated differential plate (C))
- Reworking the differential plate (C) of the existing differential case assembly (D)
In both cases the new threaded dowels would need to be installed. Reworking the existing differential plate (C) would consist of boring out the existing dowel holes of the differential plate (C). Then tapping the hole with the appropriate thread to match the new differential plate (C) specifications. Alternatively, 556-4474 Differential Case Assembly replacement part can be used which already has the new threaded holes in differential plate (C). Refer to the procedure below for specific details and the table above for part numbers.
- Reach the differential case assembly (D) by disassembling the differential and the differential lock clutch assembly. Set aside the thrust ring (B) and remove the existing three dowels (A). Refer to the Disassembly and Assembly for your machine.
If replacing the differential case assembly (D), skip to Step 7. If reworking the existing differential plate (C), continue to the next step.
- Remove differential plate (C) from the existing differential case assembly (D). Set aside the bolts and washers.
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Illustration 3 g06319635 Differential plate - Set up differential plate (C) in preparation for drilling and tapping operation on the existing three holes that dowels were removed from. Use a vertical mill or drill press to ensure that the new threads are perpendicular to the machined face of the differential plate (C).
- Drill and bore through the center of the existing three holes of differential plate (C) with 12.7 mm drill.
- Tap through the center of the same holes with M14x1.5 tool using a 15 mm diameter countersunk lead-in.
- Clean and reinstall differential plate (C) to the differential case assembly (D) using the bolts and washers set aside before. Torque the 12 M16 bolts to
270 ± 60 N·m (200 ± 44 lb ft) .Show/hide table
Illustration 4 g06319137 Dowel with threads highlighted
(A) Dowel
(E) Threads - Apply LOCTITE 620 liberally to the threads (E) of the new dowel (A).
For more information about LOCTITE 620, refer to Information Release Memo, PEGJ0075, "Cat® Henkel Loctite® Crossover Document".
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Illustration 5 g06319139 - Install by threading each of the dowels (A) into the housing until the dowel (A) bottoms out. Locking pliers with soft jaws can be used to install if needed.
- Allow the LOCTITE 620 to cure before putting the differential lock clutch in contact with oil. LOCTITE activator can be used to accelerate the cure if there is a time constraint.
- Assemble the rest of the differential lock clutch assembly per the Disassembly and Assembly for your machine.
Note: The differential group mounting bolts are highly stressed and should not be reused. Replace the bolts with new parts. Refer to the table above for assembly part numbers.
