Procedure to Update the Differential on Certain 793D and 793F Off-Highway Trucks {3258} Caterpillar

Off-Highway Truck/Tractor

793D (S/N: FDB1-UP)

793F (S/N: SND1-UP; SSP1-UP; RBT1-UP)

Introduction

This special instruction provides the required parts and the procedure to update the differential on certain 793D and 793F Off-Highway Trucks.

Do not order any parts or begin service work until the entire special instruction has been read and understood.

Reference: Disassembly and Assembly, RENR8328, "Differential and Bevel Gear - Remove"

Reference: Disassembly and Assembly, RENR8328, "Differential and Bevel Gear - Disassemble"

Reference: Disassembly and Assembly, RENR8328, "Differential and Bevel Gear - Assemble"

Reference: Disassembly and Assembly, RENR8328, "Differential and Bevel Gear - Install"

Reference: Disassembly and Assembly, KENR8397, "Differential and Bevel Gear - Remove"

Reference: Disassembly and Assembly, KENR8397, "Differential and Bevel Gear - Disassemble"

Reference: Disassembly and Assembly, KENR8397, "Differential and Bevel Gear - Assemble"

Reference: Disassembly and Assembly, KENR8397, "Differential and Bevel Gear - Install"

Required Parts

Important Safety Information

Do not perform any procedure in this special instruction until you have read this special instruction and you understand this information. Use only proper tools and observe all precautions that pertain to the use of those tools. Failure to follow these procedures can result in personal injury. The following procedures should also be observed.

Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs.

A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly.

Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard.

Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If the tools, the procedure, the work method, or your actions are not recommended by Caterpillar, ensure that the tools and your actions are safe for you and for others.

Ensure that the product will not be damaged or the product will be made unsafe by the operation, lubrication, maintenance, or the repair procedures.

Follow all safety warnings. Most accidents that involve product operation, maintenance, or repair are caused by failure to observe safety warnings. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. Personnel should be properly trained to perform maintenance, repair, or operate any machine. Safety precautions and warnings are provided this instruction and on Caterpillar products. These warnings should be observed before performing any procedures. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The warnings in this publication and on the product are not all inclusive.

The hazards are identified by the “Safety Alert Symbol” which is followed by a “Signal Word” such as “DANGER”, “WARNING” or “CAUTION”. The “WARNING” Safety Alert Symbol is shown in Illustration 1.

Illustration 1	g00008666

This safety alert symbol means:

Pay Attention!

Become Alert!

Your Safety is Involved.

The message that appears under the safety alert symbol explains the hazard.

Operations that may cause product damage are identified by "NOTICE" labels on the product and in this publication.

The information, the specifications, and the illustrations that exist in this guideline are based on information which was available at the time of publication. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Obtain the complete, most current information before you start any job. Caterpillar dealers can supply the most current information.

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Sudden movement or accidental starting of the machine can cause personal injury or death to persons on or near the machine. To prevent personal injury or death, perform the following: Park the machine on a smooth, level surface. Lower the work tool to the ground and engage the parking brake. Stop the engine and remove the key. Block the wheels and install the steering frame lock.

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When it is necessary to work under the machine with the body (bed) raised, attach the body (bed) retaining cables to the rear tow points. Install the rear tow point pins through the ends of the retaining cables. Failure to properly secure the body (bed) may result in personal injury or death.

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Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin. At operating temperature, the engine coolant is hot and under pressure. Steam can cause personal injury. Check the coolant level only after the engine has been stopped and the cooling system pressure cap is cool enough to touch with your bare hand. Remove the cooling system pressure cap slowly to relieve pressure. Cooling system conditioner contains alkali. Avoid contact with the skin and eyes to prevent personal injury.

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When a hoist is used to lift any part or assembly, stand clear of the area under the part being raised. Always make sure that the hoist has adequate lifting capacity and the wire cable is not damaged. Failure to follow this instruction could lead to injury or death. Approximate weights of the components are shown in the table which follows.

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Do not check for leaks with your hands. Pin hole (very small) leaks can result in a high velocity oil stream that will be invisible close to the hose. This oil can penetrate the skin and cause personal injury. Use cardboard or paper to locate pin hole leaks.

Installation Procedure

1. Prepare the machine for service.

2. Remove the differential and bevel gear from the machine. Refer to Disassembly and Assembly, "Differential and Bevel Gear - Remove"

3. Disassemble the differential and remove the thrust washer. Perform the disassembly procedure in Disassembly and Assembly, "Differential and Bevel Gear - Disassemble" until the thrust washer is removed from the flanged half of the differential housing.
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   Illustration 2	g03776333

4. Use Disassembly and Assembly, "Differential and Bevel Gear - Assemble" to install thrust bearing (1), thrust bearing race (2), and bevel gear (3) into the flanged half of the differential housing (4).
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   Illustration 3	g03776883
   Orientation of thrust bearing (1) to bevel gear (3)

   1. Assemble thrust bearing (1) and thrust bearing race (2) as shown in Illustrations 2 and 3.

      Note: There is no thrust bearing (1) orientation requirement relative to bevel gear (3) and thrust bearing race (2). Thrust bearing (1) must be assembled between thrust bearing race (2) and bevel gear (3). Thrust bearing race (2) must be assembled between thrust bearing (1) and differential housing (4). Refer to Illustrations 2 and 4 for proper assembly.

   2. Use Disassembly and Assembly, "Differential and Bevel Gear - Assemble" to install and tighten the screws that secure the thrust bearing.

   3. Use Disassembly and Assembly, "Differential and Bevel Gear - Assemble" to install bevel gear (3) to differential housing (4).

5. Continue using Disassembly and Assembly, "Differential and Bevel Gear - Assemble" to install the spiders and pinion gears.
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   Illustration 4	g03778616

6. Use Disassembly and Assembly, "Differential and Bevel Gear - Assemble" to install the second bevel gear (3), thrust bearing (1), and thrust bearing race (2).

   Note: Orient thrust bearing (1) onto bevel gear (3) as shown in Illustration 3.

7. Use Disassembly and Assembly, "Differential and Bevel Gear - Assemble" to install the plain half side of the differential housing (4).

   Note: Ensure thrust bearing race (2) does not come out of place when mating the two halves of differential housing (4). Thrust bearing race (2) may be fixed in place by using a small amount of 60W oil or pure petroleum jelly.

8. Use Disassembly and Assembly, "Differential and Bevel Gear - Assemble" to continue the assembly of the differential. Use Disassembly and Assembly, "Differential and Bevel Gear - Install" to install the differential into the machine.