CUMMINS 4955856 OEM MAIN BEARING SET (.010) – 5.9L/6.7L (1989–2018)

Product Description

The Cummins 4955856 OEM Main Bearing Set (.010 undersize) is a genuine, precision-engineered crankshaft main bearing set designed for 1989–2018 5.9L and 6.7L Cummins engines. These bearings are manufactured to Cummins’ exacting tolerances to deliver optimal oil film control, reduced friction, and long-term durability in high-load diesel environments. If your crankshaft has been machined .010" undersize, this is the only correct OEM bearing set for restoring factory-spec lubrication and reliability.

Whether you are rebuilding a stock work truck, restoring a high-mileage engine, or freshening up a performance build, genuine Cummins 4955856 bearings ensure proper crankshaft support and quiet, stable bottom-end operation far superior to aftermarket alternatives.

Fitment

• 1989–1993 Dodge D/W 250–350 with 5.9L 12V Cummins (6BT)
• 1994–1998 Dodge Ram 2500/3500 with 5.9L 12V Cummins (6BT)
• 1998.5–2002 Dodge Ram 2500/3500 with 5.9L 24V ISB Cummins
• 2003–2007 Dodge Ram 2500/3500 with 5.9L ISB Cummins (HPCR)
• 2007.5–2018 Dodge Ram 2500/3500 with 6.7L Cummins
• Industrial, agricultural, and commercial B-Series/ISB engines (verify by ESN)

Important: This bearing set is for crankshafts that have been ground 0.010" undersize. Always measure or confirm machining before ordering.

Cross-Reference (Cummins-Only)

Related Cummins internal engine components:
• CUMMINS 3802070 Connecting Rod Bearing Set (Standard)
• CUMMINS 3900267 Tappet Cover Bolt Grommet Seal
• CUMMINS 3915787 Oil Filter Housing / Pressure Relief Plug

FAQ

What does “.010 undersize” mean for this bearing set?

It means the crankshaft journals have been machined 0.010 inches smaller, and these OEM bearings restore correct oil clearance.

Will these bearings fit both 5.9L and 6.7L Cummins engines?

Yes — this Cummins bearing set fits all 1989–2018 B-Series / ISB / 6.7L platforms that require .010 undersize bearings.

Should I replace the thrust bearings when installing new main bearings?

Yes. Replacing the thrust bearing is standard practice during bottom-end rebuilds to maintain crankshaft end-play control.

Are aftermarket bearings acceptable for a 5.9L or 6.7L Cummins rebuild?

Aftermarket bearings vary widely in metallurgy and tolerances. Genuine Cummins bearings provide the correct crush, oil clearance, and longevity expected from a diesel bottom end.

Specifications for cummins 4955856