Product Description
Cummins 3920921 OEM P7100 Injection Pump Gear Nut For 1994-1998 5.9L Cummins 12-Valve
The Cummins 3920921 OEM P7100 Injection Pump Gear Nut is a genuine Cummins replacement fastener designed specifically for 1994-1998 Dodge Ram 5.9L Cummins 12-valve engines equipped with the Bosch P7100 injection pump. This critical retaining nut secures the injection pump gear to the P7100 pump shaft, helping maintain proper injection timing, gear retention, and long-term reliability.
Whether you're replacing a worn or damaged nut during a P-pump installation, timing adjustment, rebuild, or routine maintenance, the Cummins 3920921 provides factory-correct fitment and clamping force. As one of the most important retaining components in the Bosch P7100 fuel system, replacing fatigued hardware helps ensure reliable operation in both stock and performance diesel applications.
Features
- Genuine Cummins OEM replacement part
- Designed for Bosch P7100 injection pump applications
- Fits 1994-1998 5.9L Cummins 12-valve engines
- Secures injection pump gear to P7100 shaft
- Maintains proper injection timing integrity
- OEM-quality thread engagement and fitment
- Ideal for injection pump installation and service
- Recommended during timing adjustments and pump rebuilds
- Built to Cummins factory specifications
- Direct-fit replacement design
Fitment
- 1994 Dodge Ram 2500 5.9L Cummins 12-Valve
- 1994 Dodge Ram 3500 5.9L Cummins 12-Valve
- 1995 Dodge Ram 2500 5.9L Cummins 12-Valve
- 1995 Dodge Ram 3500 5.9L Cummins 12-Valve
- 1996 Dodge Ram 2500 5.9L Cummins 12-Valve
- 1996 Dodge Ram 3500 5.9L Cummins 12-Valve
- 1997 Dodge Ram 2500 5.9L Cummins 12-Valve
- 1997 Dodge Ram 3500 5.9L Cummins 12-Valve
- 1998 Dodge Ram 2500 5.9L Cummins 12-Valve
- 1998 Dodge Ram 3500 5.9L Cummins 12-Valve
- Fits Bosch P7100-equipped engines only
Note: This gear nut is designed specifically for Bosch P7100 injection pumps found on 1994-1998 12-valve Cummins engines. Verify your injection pump model before ordering.
What's Included
- 1 Cummins 3920921 OEM Injection Pump Gear Nut
Specifications
- Manufacturer: Cummins
- Part Number: 3920921
- Application: Bosch P7100 Injection Pump Gear Retention
- Engine Compatibility: 5.9L Cummins 12-Valve
- Fitment Years: 1994-1998
- Pump Type: Bosch P7100 (P-Pump)
- Configuration: OEM Retaining Nut
- Condition: New
- OEM Status: Genuine Cummins Part
- Function: Secures Injection Pump Gear to Pump Shaft
- Installation Location: Bosch P7100 Main Shaft
- Primary Use: Pump Installation, Timing Service, and Rebuilds
Cross Reference Numbers
3920921, Cummins 3920921, P7100 Gear Nut, Bosch P7100 Main Shaft Nut, P-Pump Gear Retaining Nut, 3920922 Lock Washer, 3918192 Injection Pump Gear, 3900250 P7100 Key
FAQ
What does the Cummins 3920921 gear nut do?
This nut secures the Bosch P7100 injection pump gear to the injection pump shaft and helps maintain proper injection timing and gear retention.
Will this fit all 5.9L Cummins engines?
No. This part is designed specifically for 1994-1998 12-valve Cummins engines equipped with the Bosch P7100 injection pump.
Should this nut be replaced during injection pump service?
Yes. Replacing critical retaining hardware during injection pump installation, timing adjustments, or rebuilds is recommended to ensure proper clamping force and long-term reliability.
Is this a genuine Cummins OEM part?
Yes. Cummins 3920921 is a genuine OEM injection pump gear retaining nut manufactured to factory specifications.
Should I replace the lock washer at the same time?
It is recommended to inspect and replace the lock washer when servicing the P7100 gear assembly. The commonly associated lock washer is Cummins part number 3920922.
Is this part suitable for performance applications?
Yes. This OEM gear nut is commonly used in both stock and performance P7100-equipped engines where proper gear retention and timing stability are critical.
