S | Technical Service Bulletin

Technical Service Bulletin: TSB230099 Released Date: 22-Jan-2024
Crankshaft Reuse Guidance After Vibration Damper Malfunction

Crankshaft Reuse Guidance After Vibration Damper
Malfunction

Warranty Statement

The information in this document has no effect on present warranty coverage or repair practices, nor
does it authorize TRP or Campaign actions.

Contents

Product Affected

¢ B6.7 CM2350 B121B
¢ B6.7 CM2450 B155B

Issue Summary
Symptom:

¢ Vibration
Root Cause:

¢ Limited crankshaft inspection procedures for reuse after vibration damper malfunction has
caused crankshafts that were out of specification to be placed back into service.

Verification

¢ Avibration damper malfunction caused from the overloading of the malfunctioning vibration
damper can lead to clamp load loss.

e Any damage to the crankshaft nose must be inspected and reviewed against the following
criteria for reuse. Figure 4 below shows an example of a reworked crankshaft.

¢ Inspect the crankshaft for reuse in chassis.

Inspection Guidelines:

¢ Visually inspect the crankshaft nose and crankshaft outer diameter for cracks and heavy
fretting.
o Use crack detection kit, Part Number 3375434 or equivalent, to check the crankshaft for
cracks.

e Replace the crankshaft if any of the following damage is found. See corresponding Service
Manual. Reference Procedure 001-016 in Section 1.
o Thread damage (extract broken cap screws for inspection)
© Distortion of the crankshaft nose / alignment boss
© Significant material removal to the outer diameter

* 01100417

Figure 1, Reusable Crankshaft Nose.

Analysis for Figure 1:
¢ This is a crankshaft with minimal damage.
Conclusion for Figure 1:

¢ This crankshaft does not require any rework to be reused.

Figure 2, Reusable Crankshaft Showing Nose Scratches and Fretting from a Vibration Damper
Malfunction.

Analysis for Figure 2:

¢ Minimal fretting on the face (Figure 2, Item 1)
¢ No damage to the alignment boss
e No damage to the cap screw hole/threads

Conclusion for Figure 2:

¢ Crankshaft is acceptable for reuse.
¢ Rework is needed to remove heavy fretting seen on the face of the crankshaft nose. Figure 4
below shows an example of the crankshaft rework.

01r00469

Figure 3, Crankshaft Nose with Severe Damage and Fretting from a Vibration Damper
Malfunction.

Analysis for Figure 3:

e Impact damage on side of the crankshaft nose edge (Figure 3, Item 1)
« Impact damage on cap screw hole (Figure 3, Item 2)
e Impact damage to the crankshaft pilot (Figure 3, Item 3)

Conclusion for Figure 3:

e If there is damage to the outer diameter of the crankshaft nose and pilot do not rework the
crankshaft.

e Replace the crankshaft, Refer to Service Procedure 001-016.

e Figure 3 has acceptable fretting, but the other outlined damage has disqualified this
crankshaft for reuse.

Resolution

Clean the crankshaft nose and install the vibration damper assembly with new components. See
the Service Parts section, Service Instructions section and Technical Service Bulletin, Repeat
Viscous Vibration Damper Capscrew Fracture Malfunctions and Viscous Vibration Damper
Replacement, TSB210097 for more information.

Service Parts

Service parts are offered. See Table 1 for part numbers.

Table 1, Service Parts

Part Description Part Number Quantity
Friction Shim 5298330 1
Dowel Pin 5305872 1

Service Instructions

¢ Remove all pieces of the fractured viscous vibration damper mounting capscrews and verify
all bullets from the Inspection Guidelines listed in the Verifications section above.

"01100470

Figure 4, Left: Crankshaft Face Rework Performed with Straight File. Right: Crankshaft showing

Acceptable Results of Rework.

e Astraight edged file can be used to remove excess material such as heavy fretting, grooves,
and scratches from the face of the crankshaft nose as shown in Figure 4.
¢ Only remove enough material that will allow a flat surface and will prevent the removal of any

base material.

¢ Do not rework the crankshaft pilot and the outside diameter of the front oil seal location.
¢ Clean the crankshaft nose of all removed debris before the vibration damper is assembled.

01r00471

Figure 5, Friction Shim Installation on Crankshaft Nose.

Assemble the vibration damper assembly with new components listed in Service Parts, Table
1.

Install friction shim, between the vibration damper and the crankshaft as shown in Figure 5.
Follow the specifications for installation of the vibration damper. See corresponding Service
Manual. Reference Procedure 001-052 in Section 1.

Perform the vibration damper face runout check below as shown in Figure 6.

Figure 6, Runout Check Procedure Being Done on Vibration Damper Face.

Vibration Damper Face Runout Check

To perform vibration damper face runout spec (wobble check):

¢ Install a dial indicator as illustrated in Figure 6.
¢ The indicator contact point should be placed 13.0 mm [ 0.50 in ] inward from the outer edge of

the vibration damper.

e Push the crankshaft to the front or rear of the engine and set the indicator to “O” (zero).
e Rotate the crankshaft one complete revolution (360 degrees) while maintaining the position of

the crankshaft, either toward the front or rear of the engine.
¢ Record the total indicator movement.

Vibration Damper Face Runout Specification

mm

0.13

MAX

0.005

¢ Ifthe vibration damper face run out specification measurement is not within specifications,

replace the damaged crankshaft.

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