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6.7L Cummins Mounting Adaptations – Flywheel – Initial Check

Inspect the flywheel ring gear teeth for damage.
If the flywheel ring gear is damaged make sure to inspect the following possible causes prior to replacing the
flex plate.
• Mechanical
• Electrical

Mechanical
A mechanical issue can typically be identified by seeing damage to the ring gear of the flywheel in 3 distinct
locations for 6 cylinder engines (commonly called 120 degree milling), and 2 locations for 4 cylinder engines
(commonly called 180 degree milling). The following can be causes for mechanical issues:
• Upon installation of the flywheel, make sure to check for proper starting motor spacing. Refer to Procedure
013-020 in Section 13.
• Interference between the ring gear land area and the starting motor pinion. The wrong starting motor can be
installed. Refer to the original equipment manufacturer’s specifications.
• There can be a defect with the starting motor pinion. Inspect the pinion for nicks and burrs. Replace the
starting motor, is necessary. Refer to Procedure 013-020 in Section 13.
• The ring gear can be improperly installed or damaged.
Refer to Procedure 016-008 in Section 16.
• The flywheel face runout may be out of specification.
See the Measure section of this procedure.
• Incorrect starting motor pinion to flywheel ring gear pitch/teeth match. Refer to the original equipment
manufacturer’s specifications.

Electrical
An electrical issue can typically be identified by seeing damage to the ring gear of the flywheel 360 degrees
around the circumference of the ring gear (commonly called 360 degree milling). The following could be causes
for electrical issues:
• Operator is attempting to start engine while engine is already running. Check if a starter lockout feature is
available through the OEM (activated with INSITETM electronic service tool) or the starting motor manufacturer.
• Key switch is causing intermittent starting motor engagement when the engine is running. Inspect the
key switch. Refer to Procedure 013-030 in Section 13.
• Orientation of the starter relay is position so the direction of the pull contact is in the direction of the
vehicle’s travel. This results in intermittent starting motor engagement when the engine is running.
Relocate the starter relay. Refer to the original equipment manufacturer’s specifications.
• Intermittent starting motor wiring issues. Refer to the original equipment manufacturer’s specifications.