Product Description
Keep your flex plate clamped to the crank the way Cummins intended with the Cummins 3908522 OEM flex plate bolt. This genuine hex-head cap screw is the exact fastener used to secure the flex plate on 1989–2018 Ram 2500/3500 trucks with the 5.9L or 6.7L Cummins diesel. It’s a torque-to-yield (single-use) bolt, sold individually—eight (8) required per flex plate for a complete service.
Unlike generic hardware-store bolts, the 3908522 is engineered for the proper shank length, thread engagement, and metallurgy to maintain clamp load through heavy towing, tuned power levels, and high-mileage use. Pair these bolts with an OEM flex plate and other Cummins genuine hardware from CPP Diesel to build a drivetrain you can trust on every key-turn.
Key Features
- Genuine Cummins 3908522 flex plate mounting bolt (hex head cap screw).
- Designed for 1989–2018 Ram 2500/3500 with 5.9L or 6.7L Cummins diesel, automatic transmission.
- Torque-to-yield (TTY) single-use fastener – always install new bolts during flex plate service.
- OE-correct length and thread pitch for proper clamp load on the crank/flex plate flange.
- Eight (8) bolts required per flex plate; sold individually so you can replace only what you need.
- Backed by Cummins quality and CPP Diesel’s Cummins genuine parts support.
Fitment
This bolt is used to mount the factory flex plate to the crankshaft on the following applications:
- 1989–1993 Ram 2500/3500 – 5.9L 12-valve (6BT), automatic transmission
- 1994–1998 Ram 2500/3500 – 5.9L 12-valve (6BT), automatic transmission
- 1998.5–2002 Ram 2500/3500 – 5.9L 24-valve ISB (VP44), automatic transmission
- 2003–2007 Ram 2500/3500 – 5.9L ISB common-rail, automatic (47RE/48RE)
- 2007.5–2018 Ram 2500/3500 – 6.7L ISB common-rail, automatic (68RFE/Aisin)
This screw also appears in various ISB/QSB industrial and off-highway applications. For non-automotive uses or engine swaps, always verify by Cummins Engine Serial Number (ESN) before ordering.
Compatibility Notes
- Automatic transmissions only – manual transmission trucks use flywheel bolts, not flex plate bolts.
- Quantity: 8 bolts required per flex plate; this listing is for a single bolt.
- TTY single-use: do not reuse removed bolts; follow Cummins/Ram torque-angle procedures.
- For edge model years or swapped transmissions, confirm fitment by VIN or ESN.
Cross-Reference & Related Cummins Parts
Use these related genuine Cummins parts from CPP Diesel when refreshing the flex plate and crankshaft interface:
- CUMMINS 3975464 OEM FLEXPLATE – RAM 5.9L (1989–2007) – Genuine drive plate that these bolts clamp to.
- CUMMINS 3946495 OEM HARMONIC BALANCER DOWEL PIN – RAM 5.9L/6.7L (2003–2018) – Aligns and pins the damper on the crank to prevent slip.
- CUMMINS 5273412 OEM CRANKSHAFT GEAR – ISB 5.9L/6.7L (2003–2018) – Drives the timing set from the crankshaft on later ISB engines.
Installation Notes
- Clean the crankshaft flange and flex plate mating surfaces; remove rust, old threadlocker, and debris.
- Install bolts clean and dry unless Cummins specifies an approved lubricant or sealant for your ESN.
- Snug all eight bolts in a star pattern to seat the plate, then complete the torque-angle sequence per the factory manual.
- After initial warm-up, recheck for drivetrain vibration or noise that could indicate flex plate or converter issues.
Specifications for cummins 3908522
| Field | Value |
|---|---|
| Brand | Cummins Genuine Parts |
| Part Number | 3908522 (flex plate mounting bolt, hex head) |
| UPC | Not specified by manufacturer |
| GTIN | Not specified by manufacturer |
| Cross Reference | Mopar 04429522 (ID/cross-reference only; verify by VIN/ESN) |
| Quantity Required | 8 bolts per flex plate (sold individually) |
| Shipping Info | Ships from CPP Diesel; small-parcel item. Catalog dimensions approx. 0.88" W × 0.88" H × 1.00" D, shipping calculated at checkout. |
| E-codes | Not applicable (engine hardware, not lighting/emissions equipment) |
| Prop 65 Warning | Yes – WARNING: This product can expose you to chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. See www.P65Warnings.ca.gov. |
FAQ
WILL THIS FLEX PLATE BOLT FIT MY 5.9L OR 6.7L CUMMINS RAM?This bolt is used on most 1989–2018 Ram 2500/3500 trucks with 5.9L or 6.7L Cummins engines and an automatic transmission. If you are unsure about edge years or swapped transmissions, confirm by VIN or Cummins ESN before ordering.
HOW MANY CUMMINS 3908522 BOLTS DO I NEED FOR ONE FLEX PLATE?
Each factory flex plate uses eight (8) of these bolts. This listing is for a single genuine Cummins bolt, so order quantity eight for a complete set when installing a new flex plate.
ARE THESE TORQUE-TO-YIELD (TTY) BOLTS, AND CAN I REUSE MY OLD ONES?
Yes. Cummins treats 3908522 as a torque-to-yield fastener. Once stretched during installation, it should not be reused. Always install new bolts during flex plate or transmission service and follow the factory torque-angle specification for your engine/transmission combination.
WHAT TORQUE SPEC SHOULD I USE FOR THESE FLEX PLATE BOLTS?
Torque specs can vary by model year and transmission. Always follow the Cummins or Ram factory service manual for your specific VIN/ESN. Use a calibrated torque wrench and angle gauge, and make sure threads are clean and dry unless the manual calls for a specific lubricant.
CAN I MIX AFTERMARKET BOLTS WITH GENUINE CUMMINS 3908522 BOLTS?
Mixing aftermarket hardware with OEM bolts is not recommended. Clamp load and stretch can differ between bolt designs. For consistent clamping force and long-term reliability, use a full matched set of genuine Cummins 3908522 bolts on every flex plate installation.
