Product Support Program For Replacing The Inter-axle Differential Thrust Washers And Inter-axle Differential Output Shaft On Certain D40D And D400D Articulated Trucks Caterpillar

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 can be administered either before or after a failure. In either case the decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS4785" as the Part Number and "7755" as the Group Number. If administered before failure, use "56" as the Warranty Claim Description Code and use " T" as the SIMS Description Code. If administered after failure, use "96" as the Warranty Claim Description Code and use " Z" as the SIMS Description Code.

NOTE: Some of the D400D Articulated Trucks fall into both groups. Do all applicable portions of this Service Letter at the same time.

NOTE: This Revised Service Letter replaces the July 9, 1992 Service Letter. Changes have been made to the Termination Date, Affected Product and Parts Needed.

Termination Date

Problem

Group 1

The inter-axle differential thrust washers may fail before achieving the desired service life on certain D40D and D400D Articulated Trucks. To reduce the possibility of thrust washer failure 6U6287 Thrust Washers need to be changed. The thrust washers should be replaced whenever SOS indicates a significant increase in copper/iron content or at 3000 hours (whichever comes first).

Group 2

On certain D400D Articulated Trucks the 7U1247 Output Shaft needs to be replaced. The service life of the original output shaft installed at the factory may be shortened due to twisting or distorting of the splines. New 7U1247 Output Shafts in parts stock (same part number) have an improved heat treatment.

Affected Product
Model & Identification Number

Group 1

D40D (2JJ1-37, 2JJ39-83, 2JJ85, 2JJ86, 2JJ88-100)

D400D (8TF1-156, 8TF158, 8TF162-193, 8TF195-335, 8TF337-341, 8TF343-570; 4EJ1-50)

Group 2

D400D (8TF259, 8TF261, 8TF263, 8TF264, 8TF266, 8TF268-276, 8TF278-344, 8TF346-351, 8TF356, 8TF358, 8TF361, 8TF364, 8TF397)

Parts Needed

Group 1

12 - 9G1777 Disc

1 - 5H4082 Seal-O-Ring

1 - 5P6026 M-wire Stk

1 - 7U1263 Washer-Thru

1 - 7U1264 Washer

9 - 7U1272 Bolt-Special

Group 2

1 - 7U1247 Shaft-Output

Action Required

Remove the inter-axle differential from the Affected Product as described in the Service Manual.

Disassemble the differential.

NOTE: The maximum allowable surface finish on the gears is 0.8 micro meter (32 mu)

Assemble the differential/drop box using the new parts.

Install the inter-axle differential in the Affected Product as described in the Service Manual.

Service Claim Allowances

NOTE: This is a 32-hour job.

Parts Disposition

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