- Articulated Truck:
- D350E (S/N: 9LR1-UP)
- D40D (S/N: 2JJ1-UP)
- D400D (S/N: 8TF1-UP)
- D400E (S/N: 2YR1-UP)
- D40D (S/N: 2JJ1-UP)
Introduction
Reference: Service Manual, SENR8692, "Disassembly and Assembly Power Train", "Gear Group - Transfer".
Reference: Service Manual, SENR8202, "Disassembly and Assembly Power Train", "Gear Group - Transfer".
This special instruction contains a procedure for the salvage of the bore for the idler gear bearing in the output transfer gear group.
If problems such as poor retention of the bearing cup, spalling or pitting are encountered with the idler bearing it may be possible to repair the transfer gear housing. Use the following procedure.
The procedure involves reboring the damaged bore in the 7U-4422 Transfer Gear Case and the 139-9129 Transfer Gear Case in order to insert a sleeve. The sleeve provides more material behind the bearing cup in order to provide increased retention for the bearing in the case. A new solid steel carrier plate replaces the previous cast iron 7U-1329 Carrier Plate . The new carrier plate must be manufactured to the specifications that are contained later in this Special Instruction. The new carrier plate provides increased axial stiffness of the case. These modifications offer an increased service life for the bearing.
Salvage Procedure for the Transfer Gear Housing
Removal and Inspection of the Transfer Gear Housing
The transfer gear group must be removed from the machine and disassembled in order to allow access to the area of the transfer gear housing to be modified.
Refer to the Disassembly and Assembly.
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| Illustration 1 | g00750633 |
Inspect for wear or damage to the bores in the transfer gear housing | |
Once the components of the transfer gear group have been removed from the transfer gear housing inspect the bores for the idler gear bearings in the transfer gear housing for wear or damage. Refer to Illustration 1. It will be necessary to replace the transfer gear housing if there is excessive wear or damage to the bores for the other bearings in the transfer gear group. New 139-9129 Transfer Gear Cases have already been modified. It will still be necessary to replace the 7U-1329 Carrier Plate with the new solid steel Carrier Plate .
Manufacture of the Sleeve
Manufacture a sleeve to the dimensions that are given in Illustration 2. Use a suitable steel with a minimum yield strength of 207 MPa (30022 psi).
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| Illustration 2 | g00750634 |
Manufacture the Sleeve for the Front Idler Bearing. All dimensions are in millimeters. | |
Manufacture of New Carrier Plate
Manufacture a new solid steel carrier plate. Use a suitable steel with a minimum yield strength of 207 MPa (30022 psi). Refer to Illustration 3.
If suitable facilities are not available for the manufacture of the carrier plate, the carrier plate can be obtained through the Caterpillar parts system.
Note: The 197-6814 Carrier Plate will be made to order.
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| Illustration 3 | g00750638 |
Solid steel carrier plate (A) The holes that surround bore (1) and bore (2) are identical. (B) All dimensions are in millimeters. | |
Preparation of the Gear Case Group and Installation of the Sleeve
Install the carrier plate to the transfer gear housing.
Prepare the bore for the front idler bearing. Use suitable equipment to line bore the bore for the front idler bearing. Ensure that the centerline of the bore for the front idler bearing is aligned with the centerline of the bore in the carrier plate. Use the dimensions that are given in Illustration 4. The diameter of the bore is critical in order to allow an interference fit between the bore and the sleeve.
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| Illustration 4 | g00750635 |
Preparation of the transfer gear housing for installation of the sleeve All dimensions are in millimeters. | |
The sleeve is an interference fit into the bore. It will be necessary to lower the temperature of the sleeve in order to allow installation. Use a suitable method to lower the temperature of the sleeve.
Refer to Illustration 5. Ensure that the sleeve is installed correctly, and allow the sleeve to warm to ambient temperature. Once the sleeve has warmed, the sleeve must be machined in position in order to ensure the correct alignment with the bores for the other bearings in the transfer gear housing.
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| Illustration 5 | g00750637 |
Installation of the Sleeve and Machining of the sleeve All dimensions are in millimeters. | |
Reassembly of the Transfer Gear Case Group
Once the transfer gear housing has been modified and the solid steel carrier plate has been manufactured, the transfer gear case group can be reassembled. Refer to the Disassembly and Assembly manual.