Product Description
The CUMMINS 4089976 OEM PISTON & RING KIT (.020 OVER) is designed for 2003–2004 5.9L ISB Cummins 305HP diesel engines. This genuine Cummins piston and ring kit is manufactured to OEM specifications and is intended for engine rebuilding applications requiring a .020-inch oversize piston.
Use this kit when rebuilding a worn engine block that has been machined .020-inch over standard bore size. Proper piston-to-cylinder clearance is critical for engine performance, durability, and oil control. Always verify fitment by CPL number, engine serial number, and machine shop measurements before ordering.
FEATURES
- Genuine Cummins OEM piston and ring kit
- .020-inch oversize piston for rebuilt engine applications
- Designed for 2003–2004 ISB 5.9L 305HP engines
- Includes matched piston and piston ring package
- Manufactured to OEM Cummins specifications
- Ideal for engine overhauls and rebuild projects
FITMENT
- 2003–2004 Dodge Ram 2500 5.9L Cummins 305HP
- 2003–2004 Dodge Ram 3500 5.9L Cummins 305HP
- Select Cummins ISB 5.9L industrial applications using the applicable CPL
WHAT'S INCLUDED
- 1 Cummins 4089976 OEM Piston (.020 Over)
- 1 Matching Cummins Piston Ring Set
CROSS-REFERENCE AND RELATED PRODUCTS
- Cummins 4089976
- Cummins Standard Bore Piston & Ring Kits
- Cummins Connecting Rod Bearings
- Cummins Main Bearing Sets
- Cummins Complete Engine Rebuild Components
SPECIFICATIONS
- Manufacturer: Cummins
- Part Number: 4089976
- Part Type: Piston & Ring Kit
- Engine Compatibility: ISB 5.9L Cummins 305HP
- Fitment Years: 2003–2004
- Vehicle Application: Dodge Ram 2500 / 3500
- Bore Size: .020 Over
- Condition: New OEM Cummins
- Installation Type: Engine Rebuild / Overhaul
FAQ
Will this piston kit fit my truck?
This piston kit is designed for specific 2003–2004 5.9L ISB Cummins 305HP applications. Always verify your engine serial number, CPL, and bore size before ordering.
What does .020 over mean?
A .020 over piston is designed for an engine block that has been machined .020-inch larger than the factory bore size during a rebuild.
Does this kit include piston rings?
Yes. The Cummins 4089976 kit includes both the piston and matching piston ring set.
Can I install this in a standard bore engine?
No. This piston is intended only for engines that have been machined to a .020-inch oversize bore specification.
Is this a genuine Cummins component?
Yes. Cummins 4089976 is a genuine OEM Cummins piston and ring kit manufactured to factory specifications.
Do I need any related parts?
During an engine rebuild, inspect cylinder liners, bearings, connecting rods, wrist pins, gaskets, seals, and related rotating assembly components and replace them as necessary.
