For automotive and industrial applications, inspect the flex plate ring gear teeth for damage.
If the flex plate ring gear is damaged make sure to inspect the following possible causes prior to replacing the
flex plate.
Mechanical
A mechanical issue can typically be identified by seeing damage to the ring gear of the flex plate 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 could be causes for mechanical issues:
• Upon installation of the flex plate, 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, if necessary. Refer to Procedure 013-020 in Section 13.
• Torque Converter/transmission is damaged/incorrectly mounted. Refer to the original equipment
manufacturer’s specifications
• Incorrect starting motor pinion to flex plate 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 the INSITETM electronic service tool) or the starting motor
manufacturer
• Key switch 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 so that 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.
