PSP FOR TIMING ADVANCE SLIPPAGE ON CERTAIN 3406B TRUCK ENGINES - EFFECTIVE OCTOBER 09, 1990 - PS6042 - THIS SL REPLACES POR TION OF MAY 17, 1990 SL - PS4300 - INVOLVING 3406B TRUCK ENGINES - MAILED US AND CANADA, COFA, CFEL, TRUCK TEPS - LIMITE D COS Caterpillar

(Effective October 9, 1990)
U-242
AU-153
E-148
O-183.5
TT-21
1272   PS6042
NOTE: This Program can only be administered after a failure
occurs. The decision whether to apply the Program is made
by the dealer. When reporting the repair, use "PS6042" as
Part Number, "7755" as Group Number, and "96" as
Description Code.
NOTE: This Service Letter replaces the portion of the May 17, 1990
Service Letter - PS4300 involving 3406B Truck Engines.

December 31, 1991

The 7C5902 Body As. can slip in the 7W5242 Carrier As. in the Fuel Pump &
Governor Drive Group (Timing Advance) used in certain 3406B Truck Engines
(1988 model and later). The new parts listed under the heading Parts
Neededwill not fit 1987 and earlier models.

Model Identification Number
3406B 4MG3600 - 92794

1 - 7E2460 Race (use only if required)
1 - 7E8097 Carrier As.
4 - 7N7264 Weight (use only if required)
1 - 2W0459 Gasket
1 - 4W0436 Seal (use only if required)
2 - 4W2754 Seal (use only if required)

See the attached procedure.

Product Caterpillar Dealer Suggested Customer Suggested
miles/age Parts Labor Hrs. Parts Labor Hrs. Parts Labor Hrs.
whichever
comes
first
0-300,000 100% 2.5 0 0 0 0
0-60
NOTE: This is a 2.5-hour job.

Any parts removed (with the exception of cores used for Caterpillar
Remanufactured parts) can be rendered useless and scrapped immediately upon
completion of the repair.
Attach. (1-Rework Procedure)
Rework Procedure
Many factors unrelated to the timing advance can contribute to poor truck
performance. Refer to the Truck Performance Diagnostic Guide Form No.
SEBD0808. If body/carrier slippage is suspected, pin the injection pump and
remove the fuel pump & governor drive group (timing advance) from engine.
Disassemble the timing advance for access to the body/carrier assembly.
Engine Serial Numbers 4MG3600-16829
Perform the following inspection to determine body/carrier slippage:
1) Try to rotate the body in the carrier by hand. If the body slips in
the carrier, install the parts listed under Parts Needed.
2) If the body does not rotate in the carrier, inspect the inside surface
of the body which contacts the spline end of the fuel pump camshaft.
A thin contact line on this surface is normal. If a wider contact
line is present with evidence of metal displacement or spalling,
body/carrier slippage has likely occurred. A second location to check
is the other side of the body which contacts the large 8F1145 Lock
Ring (See Illustration for wear locations). If the body has slipped,
the harder ring material will wear (or polish) the outer contact face
of the body. Look for polishing in the open area between the ends of
the 8F1145 Lock Ring. If both wear conditions are found, install the
parts listed under Parts Needed.
Engine Serial Numbers 4MG16830-92794
On engines with serial numbers 4MG16830 and up, alignment marks are
stamped on the front of the 7C5902 Body and 7W5242 Carrier (See
Illustration). If the marks are aligned, body/carrier slippage has
likely not occurred. Do not replace the parts.
If the marks are not aligned (within 5 degrees), install the parts listed
under Parts Needed.
All Engine Serial Numbers Above
Engine serial numbers 4MG57673 and up are equipped with dual 7E2460 Races
(top hat design). Engines from 4MG3600 to 4MG57673 may have been
updated. Refer to May 17, 1989 Service Letter - PS4300 for additional
information.
Before the flyweights and races are assembled, inspect the four 7N7264
Flyweights and the 7E2460 Race in contact with the flyweights. Some wear
on the contact face of the race
is normal, but if race wear depth is greater than 1/2 the thickness of
the race, replace the race and all four flyweights.
Assemble the timing advance group and install on engine. Verify correct
engine dynamic timing using the 6V3100 or 8T5300 Timing Indicator Group.
****** IMAGE: SEBE4462.00001.001
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