Cummins 3908522 — Genuine Flex Plate Bolt (Hex Head Cap Screw) for 5.9L & 6.7L

MPN: 3908522  |  Also Known As: flexplate bolt, crank-to-flex plate bolt, hexagon head cap screw  |  Cross-Refs (ID only): Mopar 04429522

Genuine Cummins fastener that secures the flex plate to the crankshaft on Ram trucks with the 5.9L and 6.7L Cummins diesel. Sold individually; eight (8) required per flex plate. This is a torque-to-yield (TTY) fastener—replace anytime removed.

Features & Benefits

• OE-grade metallurgy & length for correct clamp load on flex plate/crank flange.
• Torque-to-yield design for consistent, reliable clamping (single-use).
• Hex-head cap screw style for proper socket engagement and serviceability.
• Direct OE replacement—no guesswork on thread pitch or shank length.
• Backed by Cummins quality for durability under towing and performance use.

Verified Fitment (Automotive)

Industrial/Off-Highway: This screw appears across multiple ISB/QSB applications; verify by ESN if ordering for non-automotive uses.

Specifications

• Type: Flex plate mounting bolt (hex head cap screw)
• OE Part Number: 3908522
• Quantity Required: 8 per engine (sold individually)
• Service Note: Torque-to-yield; install new bolts and follow factory torque/angle.
• Cross-Reference (ID only): Mopar 04429522

What’s In The Box

• (1) Genuine Cummins Flex Plate Bolt (3908522)

Installation Tips

• Replace all 8 bolts together; never mix old and new.
• Clean crank flange and flex plate mating surfaces; ensure correct flex plate orientation.
• Install dry unless the service manual specifies otherwise; follow torque + angle pattern in a star sequence.
• Recheck torque after initial rotation only if the OEM procedure calls for it—do not “retorque” TTY bolts after cycling.

FAQ

HOW MANY BOLTS DO I NEED?

Eight (8) bolts are required per flex plate; this listing is for a single bolt so order quantity 8 for a complete set.

ARE THESE TORQUE-TO-YIELD (TTY), AND CAN I REUSE THEM?

Yes—these are TTY fasteners and should not be reused. Always install new bolts and follow the OEM torque/angle spec.

DOES 3908522 FIT BOTH 5.9L AND 6.7L RAMS?

Yes—covers automotive applications from 1989–2018 5.9L & 6.7L Cummins (automatic). Verify by VIN/ESN for edge years.

IS THIS FOR MANUAL TRANSMISSIONS?

No—this is the crank-to-flex plate bolt for automatic trucks. Manual transmissions use flywheel bolts.

DO I NEED THREADLOCKER OR OIL ON THE THREADS?

Install per the Cummins/Chrysler service procedure. Many TTY fasteners install dry; don’t add oil or threadlocker unless specified.