Product Description
Cummins 4955855 — Main Bearing Set (Standard) for B-Series / ISB
MPN: 4955855 | Also Known As: main bearing kit, crankshaft main bearings (STD) | Supersedes / Related: 3802010 (superseded), 4955856 (.010), 4955857 (.020)
Why This Part
- ✓ OE bearing geometry for proper oil film control and crank support.
- ✓ Direct-fit STD size for stock crankshafts (no machining required).
- ✓ Complete set with mains and thrust to refresh the bottom end.
- ✓ Genuine Cummins materials and QC for durability and service life.
Quick Specs
| Type | Main bearing set (standard size) |
|---|---|
| OE Part # | 4955855 (supersedes 3802010) |
| Contents (typical) | 4× 3978818 (mains), 5× 3978820 (mains), 1× 4938948 (thrust) |
| Qty Required | 1 set per engine |
| Undersizes | .010 = 4955856 | .020 = 4955857 |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 1989–2002 | 5.9L B-Series / ISB (12V & early 24V) | Dodge/Ram 2500/3500 |
| 2003–2007 | 5.9L ISB (24V Common-Rail) | Ram 2500/3500 |
| 2007.5–2018 | 6.7L ISB (verify by ESN) | Ram 2500/3500 |
Industrial/Off-Highway: Common across B-Series families (4B3.9, 6B5.9, ISB/QSB 4.5/5.9/6.7). Always confirm by ESN due to running changes.
Often Paired With
- Lower Engine Gasket Set (6.7L): 4955522
- Main Bearing Cap Bolts: 3927948 (set of 14 required)
- Undersize Sets (if journal is ground): 4955856 (.010) & 4955857 (.020)
- Fresh oil & filter after bottom-end service
What’s In The Box
- (1) Genuine Cummins Main Bearing Set — Standard size (4955855)
- Includes mains and thrust bearing (see contents above)
Install Tips
- Measure journals; verify STD size before installation. Use Plastigage to confirm clearance.
- Clean oil passages; oil bearings during assembly. Torque caps to spec and verify crank endplay.
- If the crank is ground undersize, order 4955856 (.010) or 4955857 (.020) instead of STD.
FAQ
WILL THIS FIT 5.9L AND 6.7L CUMMINS RAMS?It’s the OE standard-size set used across many B-Series applications (5.9L/6.7L). Always confirm by VIN/ESN for 6.7L due to running changes.
IS THIS A STANDARD (STD) SIZE SET?Yes—4955855 is the STD size. Undersizes are 4955856 (.010) and 4955857 (.020).
DOES THE KIT INCLUDE THE THRUST BEARING?Yes—typical contents include the thrust bearing (4938948) along with the main shells.
WHAT ELSE SHOULD I REPLACE DURING A BOTTOM-END RESEAL?Consider new main cap bolts (3927948) and a lower engine gasket set (6.7L: 4955522). Clean and inspect all components.
WHAT NUMBER DID THIS SUPERSEDE?4955855 supersedes 3802010 in many catalog listings.
