Reusability Inspection of Certain Planetary Gear Needle Bearings for 797 Transmissions {3030, 3160} Caterpillar

Off-Highway Truck/Tractor

797 (S/N: 5YW1-UP)

797B (S/N: JSM1-UP)

797F (S/N: LAJ1-UP; WSP1-UP; LTZ1-UP)

Introduction

© 2018 Caterpillar All Rights Reserved. This guideline is for the use of Cat dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law.

Information contained in this document is considered Caterpillar: Confidential Yellow.

This Reuse and Salvage Guideline contains the necessary information to allow a dealer to establish a parts reusability program. Reuse and salvage information enables Caterpillar dealers and customers to benefit from cost reductions. Every effort has been made to provide the most current information that is known to Caterpillar. Continuing improvement and advancement of product design might have caused changes to your product which are not included in this publication. This Reuse and Salvage Guideline must be used with the latest technical information that is available from Caterpillar.

For technical questions when using this document, work with your Dealer Technical Communicator (TC).

To report suspected errors, inaccuracies, or suggestions regarding the document, submit a form for feedback in the Service Information System (SIS Web) interface.

Canceled Part Numbers and Replaced Part Numbers

This document may include canceled part numbers and replaced part numbers. Use the Numerical Part Record (NPR) on the Service Information System Website (SIS Web) for information about canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.

Note: This document can be used for reuse inspection procedures of the 797 transmission planetary carrier (TR5 & TR6) gear needle bearing Cat part numbers 192-9969 and 274-5106.

Important Safety Information

Illustration 1	g02139237

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 a tool, a procedure, a work method, or operating technique that is not recommended by Caterpillar is used, ensure that it is safe for you and for other people to use. Ensure that the product will not be damaged or the product will not be made unsafe by the operation, lubrication, maintenance, or the repair procedures that are used.

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Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death. Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood the operation, lubrication, maintenance and repair information.

Safety precautions and warnings are provided in this manual and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons.

The hazards are identified by the “Safety Alert Symbol” which is followed by a “Signal Word” such as “DANGER”, “WARNING” or “CAUTION”. Refer to Illustration 2 for an example of a “WARNING” Safety Alert Symbol.

Illustration 2	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.

Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The safety information in this document and the safety information on the machine are not all inclusive. Determine that the tools, procedures, work methods, and operating techniques are safe. Determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Also, determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.

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.

Summary

This guideline provides the procedures necessary to determine the reusability of the 797 transmission planetary carrier (TR5 & TR6) gear needle bearings. Life will vary depending on application, load, lubrication, and environment.

This guideline contains the latest standards of engineering, which will help minimize owning and operating costs. A part is expected to reach the next Planned Component Rebuild (PCR) if the part meets the specifications within this guideline and the part is intended for a similar application. Use this guideline to determine whether a part should be reused. Do not install a part that is not reusable. During reconditioning, correct any condition that might have caused the original failure.

Needle bearings can be reused to complete transmission PCR life for Non-Zero Hour Rebuild under compliance with Reuse and Salvage Guidelines, M0090315, "Reusability Inspection of Planetary Gear Needle Bearings for 797 Transmissions". Needle bearings shall not be reused for more than one PCR cycle. Therefore, it is critical to mark the needle bearings to prevent another use. Refer to the "Specialized Bearing Marking Procedure" section.

Follow visual inspections and the "Visual Surface Inspection Method" section for further guidance.

References

Service Advisories, Service Letters, and Technical Service Bulletins

Information

Illustration 3	g06272404
(A) Planetary Group (B) Planetary Carrier (TR5) (C) Carrier Assembly (TR6) (1) Bearing (2) Bearing

Tooling and Equipment

Note: The Tooling and Equipment in Table 4 is not an all inclusive list of Tooling required to perform every task within this document. Tooling needs may vary for scope of work to be performed for each specific rebuild.

Preparation Recommendations

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Personal injury can result when using cleaner solvents. To help prevent personal injury, follow the instructions and warnings on the cleaner solvent container before using.

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Personal injury can result from air pressure. Personal injury can result without following proper procedure. When using pressure air, wear a protective face shield and protective clothing. Maximum air pressure at the nozzle must be less than 205 kPa (30 psi) for cleaning purposes.

Note: Clean exterior of the 797 transmission prior to disassembly to minimize cross-contamination.

• Before you inspect a part, clean the part thoroughly to ensure that all components are free from rust, oil, burrs, and debris prior to inspection. A surface irregularity can hide the indication of an unacceptable defect.

• Bearings shall be cleaned in a cold parts washer to remove any debris.

• During cleaning and handling, do not damage any of the bearing surfaces.

• Use pressurized air to dry the bearings.

Note: The tanks for dipping should be covered when parts are not being coated.

• Dip bearings in SAE 30 TDTO (Transmission/ Drive Train Oil) to prevent rust or corrosion if inspection is not done immediately after cleaning. Spraying or brushing coating on does not sufficiently cover the surfaces of the bearing rollers and the cage. Carefully store the parts in a clean container.

Storage Instructions:

Note: Ensure that preparation recommendations are completed before storage instructions.

• Dip bearings in SAE 30 TDTO (Transmission/ Drive Train Oil) to prevent rust or corrosion if inspection is not done immediately after cleaning. Carefully store the parts in a clean container.

• Once coated, the bearings should be wrapped in a Volatile Corrosion Inhibitor (VCI). VCI paper is recommended. Seal the bearings in a plastic bag. Wrapped bearings should be stored in a clean, dry place.

• Utilize a storage box to protect the bearings and prevent handling damage. Caterpillar recommends using the same boxes and packaging that are used to ship the new bearings.

Specialized Bearing Marking Procedure

The code used in this application is an (X) and is used to record the history of mid-life use needle bearing part numbers 192-9969 and 274-5106 only. The code will identify that the needle bearing has been used once and therefore shall be replaced on the next rebuild. This information is important and should be considered for any decision to reuse a needle bearing.

Illustration 4	g06124077
DO NOT use numbering stamp punches to mark internal components.

The procedure for marking needle bearings is a Cat standard. This code is helpful when the machine is sold into a different territory after the first rebuild. The needle bearings should be marked on the surface of the transition of the bar. This surface has the least amount of wear against mating components. During an overhaul, an (X) indicates that the needle bearings have been reused one time and shall not be used again.

Example 1

Illustration 5	g06273730
(1) Bearing (2) Bearing (A) Serial Number on the bar. (B) Mark on bar transition.

Note: It is not necessary to ensure that the needle bearings are installed as a set or required to be installed in the same locations that the needle bearings were removed originally.

Use a metal marking pen to mark an (X) onto the bar transition next to the serial number. The serial number should be on a bar.

Bearing Characteristics

Illustration 6	g06275894
Needle Bearings are subject to radial loads.

Needle bearings are cylindrical roller anti-friction bearings that have rollers with a length and width ratio of greater than 4:1. These needle bearings are used for radial loads on planetary pin shafts.

• Anti-Friction

• Cylindrical Roller

• Rollers with a length and width ratio of greater than 4:1

• Carry radial loads

• Support planetary gears

Glossary of Terms

• Abrasive Wear - Abrasives such as dirt or sand in lube systems can also cause bearing failures. If contamination is extensive, bearings can lock up, cause rollers to slide generating adhesive wear, and/or cause races to move in housings or on shafts. If abrasives cause bearings to progress to adhesive wear or spalling, the root cause will be difficult to determine by looking at only the failed bearing. Careful observation of other parts in the same lubrication system however, will generally give evidence of system contamination. Look for the matte or satin finish on other bearings and gears lubricated by the same oil. If there is evidence of abrasive wear, then determine the exact source of the abrasive material. Using magnification to identify what type particle caused the wear is a good practice.

• Adhesive Wear - Adhesive wear, without extreme plastic deformation, can occur on race and rolling element surfaces if there is insufficient cool oil to control heat and if rollers stop turning and start sliding. Rollers can stop turning if the cage is excessively worn or broken allowing rollers to skew and start skidding on raceways.

• Black Acid Etching - Black acid etching is a type of corrosion that affects the surfaces of the rollers of the bearing. Black acid etching is caused through a reaction of temperature and certain oils. Black acid etching can progress from a visual imperfection into damage on the surface that can make the bearing unusable.

• Bruising - The damage can be caused by large particles and contaminants in the lubricant. The metal from a gear or the metal from the failure of a bearing are large particles that can cause bruising. The particles can cause plastic yielding and denting in raceways and on rollers. Hard particles will produce sharp angular dents while softer particles will produce smoother, shallower dents. If the bruising is sharp and angular, the bruising normally leads to spalling.

• Corrosion - Corrosion is damage on the surface that is caused by moisture on the bearing surfaces or by moisture in the lubrication system. One type of corrosion is rust, which can develop after the bearing is cleaned. Without a thin film of oil, the bearing can rust rapidly. If moisture is in the lubrication system, corrosion will take place while the machine is shut down. The condition is known as static corrosion or black acid etching.

• Handling, Installation, and Removal Damage - Handling damage consists of any damage that is a result of not handling the bearings properly. Damage from installation is often physical damage to the bearing. The damage is caused by improper installation or removal.

• Scoring - Scoring is a small cut or a small groove that extends around the part. Scoring can take place on the roller or cup cage. Scoring is most often caused by foreign particles in the oil.

Inspection Procedure

Illustration 7	g06275903
Needle Bearing Critical Features (A) Cage Face (B) Cage (C) Bar Transition (D) Bar (E) Roller (F) Cage Corner Pockets

Note: It is not necessary to remove the rollers from the cage for this inspection.

1. Complete an initial visual inspection of the bearing. DO NOT USE PART AGAIN, if a bearing has any of the following wear:

   • Handling, installation, and removal damage

   • Corrosion

   • Fine grain contact stress fatigue or spalling of the rollers

   • Moderate to severe denting or bruising on the rollers

   • Pitting of the rollers

   • Moderate to severe abrasive wear of the bearing cage

   • Fractures of the bearing cage structure, typically propagates from the cage corner pockets

   • Adhesive wear of the bearing cage side faces

   Note: Good lighting and magnification may be necessary, refer to Table 4 for tooling part numbers.

2. Complete a detailed inspection of the needle bearings.

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When replacement parts are required for this product Caterpillar recommends using Caterpillar replacement parts or parts with equivalent specifications including, but not limited to, physical dimensions, type, strength and material. Failure to heed this warning can lead to premature failures, product damage, personal injury or death.

Visual Examples

Illustration 8	g06276328
Note: The cage of bearing (1) is phosphate coated and thus will have a darker appearance than of bearing (1). (1) Bearing (2) Bearing

Illustration 9	g06276646
Example of corrosion found on a bearing roller. Bearings that exhibit oxide residues on the surface or have indications of pitting damage as a result of previous surface corrosion. If any corrosion is found on the bearing rollers, DO NOT USE AGAIN.

Illustration 10	g06276329
Example of black acid etching (A) to rollers, DO NOT USE THIS PART AGAIN. (A) Black Acid Etching

Illustration 11	g06276663
Example of fine grain spalling, DO NOT USE AGAIN.

Illustration 12	g06276643
Use a seal pick to assess any wear of the roller surface. If the seal pick catches or the traversed surface has a rough feel as the seal pick is drug across the surface, then DO NOT REUSE.

Illustration 13	g06276820
Example of polishing from light contact on rollers in the same locations. This contact is normal and is a result of the roller guides that are located where the transition meets the bar. If polishing becomes scoring, then perform the seal pick test. If rollers pass the seal pick test, then OK USE AGAIN.

Illustration 14	g06276711
Example of wear of the roller. If wear passes the seal pick test, then OK USE AGAIN.

Illustration 15	g06276720
Typical example of rollers with numerous small bruises. If bruising is found on more than five rollers, then DO NOT USE PART AGAIN.

Illustration 16	g06276683
Use a seal pick to assess damage to the bearing cage contact area. If the seal pick catches or the abraded area has a rough feel as the seal pick is drug across the surface, then DO NOT USE AGAIN.

Illustration 17	g06276667
Example of a crack found in the corner pocket of the bearing cage. Use a microscope or a magnifying glass to inspect the corner pockets of the cage structure for crack initiation. If any cracking of the cage is found, DO NOT USE AGAIN.

Illustration 18	g06276675
Example of a crack found in the corner pocket of the bearing cage. Use a microscope or a magnifying glass to inspect the corner pockets of the cage structure for crack initiation. If any cracking of the cage is found, DO NOT USE AGAIN.

Illustration 19	g06276334
Example of determining the reusability of the cage face using seal pick (B). (B) Seal Pick

Note: Drag seal pick (B) against the radial wear or in the direction of the arrows, to obtain the best results.

Use seal pick (B) to assess damage on the cage side face. If the seal pick catches or the traversed surface has a rough feel as the seal pick is drug across the surface, then DO NOT USE AGAIN.

Illustration 20	g06276653
Example of corrosion found on a cage face. If any corrosion is found on the cage, DO NOT USE AGAIN.

Illustration 21	g06276694
Example of marking of the phosphate coating found on a cage face. If wear passes the seal pick test, then OK USE AGAIN.

Visual Surface Inspection Method

Visual Surface Inspection (VT) is a method for testing components for cracks without damaging the component. Refer to Table 5 for advantages and disadvantages and Table 6 for standards and requirements for these NDT methods.

Visual Surface Inspection (VT)

Illustration 22	g06124166
Example of Visual Surface Inspection (VT) Tooling (A) Flashlight (or adequate light source) (B) Magnifying Glass (C) Tape Measure (or other measuring device) (D) Inspection Mirror

Illustration 23	g06085442
Illustration of view through eye piece of a pocket microscope.

If necessary use a microscope with light for enhanced view and to measure the defects. Refer to Tooling Table 4 for the part numbers.

Visual Surface Inspection (VT). VT is often the most cost-effective inspection method and requires little equipment as seen in Illustration22 or optional 23. Personnel performing VT shall either be trained to a company standard or have sufficient experience and knowledge regarding the components being inspected. Personnel performing VT shall take routine eye exams.