A Support Plate Needs To Be Installed On The Torque Converter Impeller Of Certain 518C Grapple Skidders Caterpillar

A Support Plate Needs To Be Installed On The Torque Converter Impeller Of Certain 518C Grapple Skidders

Usage:

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Caterpillar: Confidential Yellow

NOTE: The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.

NOTE: This Program must be administered as soon as possible. When reporting the repair, use "PI3783" as the Part Number, "7751" as the Group Number, "56" as the Warranty Claim Description Code and "T" as the SIMS Description Code. Exception: If the repair is done after failure, use "PI3783" as the Part Number, "7751" as the Group Number, "96" as the Warranty Claim Description Code, and "Z" as the SIMS Description Code.

Completion Date

Febuary 29, 1996

Termination Date

August 31, 1996

Problem

The 1T1051 Impeller in 1T1986 Torque Converter Groups in certain 518C Grapple Skidders may crack around the inner bolt circle. Oil leakage through these cracks can cause low rimpull and/or powertrain overheating.

Affected Product
Model & Identification Number

518C (9HJ442-459, 9HJ474-951, 9HJ990)

NOTE: In addition to the products listed above, this Program also applies to any 518C Grapple Skidders (S/N prefix 9HJ) that were previously reworked in accordance with PS8044, Service Letter dated February 28, 1994.

Parts Needed

Dealers will need to order parts for this Program.

24 - 4B3388 Bolt

8 - 1T0720 Bolt-12 Point

1 - 1T2015 Plate

NOTE: If a 1T2015 Plate is not available, a 1T1629 Plate can be modified to be used instead.

Action Required

See the attached procedure.

Owner Notification

U.S. and Canadian owners will receive the attached Owner Notification.

Service Claim Allowances

NOTE: This is a 40-hour job. In addition to the 40 hours of labor listed above, up to another 5 hours of labor (or a maximum of $200 USD) may be claimed for machining the 1T1059 Gear and/or 1T1629 Plate.

NOTE: U.S. and Canadian Dealers Only - This Program does not qualify for a Type 2 SIMS Report.

Parts Disposition

Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.

NOTE: MAKE EVERY EFFORT TO COMPLETE THIS PROGRAM AS SOON AS POSSIBLE.

Attach.

(1-Owner Notification)

(2-Rework Procedure)

Copy Of Owner Notification For U.S. And Canadian Owners

Rework Procedure

1. Remove and disassemble the torque converter as described in the Service Manual.

2. If a 1T2015 Plate is unavailable for this rework, obtain a 1T1629 Plate and machine it as shown in Illustration 1 to provide adequate clearance between the 4B3388 Bolts and the pump drive gear.

3. Machine the 1T1059 Gear Assembly as shown in Illustration 2. Because the gear is very hard, the face modification will need to be performed on a grinder. Also, the tapped holes need to be deepened as much as possible with a bottom tap.

NOTE: After the gear modifications are completed, and before assembly is attempted, ensure that the threaded holes are deep enough by installing a 1T0720 Bolt in each hole and measuring the distance between the bottom of the bolt head and the surface of the gear. This dimension should be 18.5 mm (.73 in) or less to ensure that the stackup of parts gets clamped properly. If the threaded holes cannot be deepened enough to attain that dimension, shorten all eight of the 1T0720 Bolts an equal amount that is sufficient to attain the 18.5 mm (.73 in) dimension.

4. Carefully inspect the inner flange of the existing 1T1051 Impeller for cracks. If none are found, the impeller should be reused. If cracks are found, a new 1T1051 Impeller should be installed.

5. Assemble the torque converter group according to Illustration 3 and the procedures in the Service Manual. Tighten the 1T0720 Bolts to a torque of 50 ± 7 N·m (37 ± 5 lb ft). Tighten the 4B3388 Bolts to a torque of 30 ± 5 N·m (22 ± 4 lb ft).

NOTE: Even if a failure has occurred, there may not be significant contamination of the cooler and planetary group if the failure is detected early enough. A careful inspection of the converter wheels will indicate the extent of the cleanup and repair work needed:

A. If there is substantial wear of the wheels from rubbing each other, the entire transmission arrangement and system will require cleaning.

B. If there has been little or no contact between the wheels, the planetary group, cooler and lines should not be contaminated.

The cleanliness of the control valve group can also be used to assess the degree of the system contamination.

6. Clean other system components as required, complete assembly of the transmission arrangement, and install the transmission in the machine as described in the Service Manual.

Illustration 1