Product Description
Cummins 4891178 — Connecting Rod Wrist Pin Bushing (Small-End / Piston Pin Bushing)
MPN: 4891178 | Also Known As: piston pin bushing, small-end rod bushing | Cross-Refs: 3901085, 3941476
Why This Part
- ✓ OE bushing for precise wrist-pin support and quiet operation.
- ✓ Direct-fit for Dodge Ram 5.9L Cummins (1989–2007; verify by ESN/rod style).
- ✓ Restores correct clearance after rod reconditioning or rebuild.
- ✓ Sold individually; 6 required per engine.
Quick Specs
| Type | Connecting rod wrist pin (piston pin) bushing, small end |
|---|---|
| OE Part # | 4891178 |
| Cross-References | 3901085, 3941476 |
| Qty Required | 6 per engine (sold individually) |
Verified Fitment (Automotive)
| Year Range | Engine | Chassis |
|---|---|---|
| 1989–1993 | 5.9L 12V 6BT (Mechanical) | Ram 2500/3500 |
| 1994–1998 | 5.9L 12V (P7100) | Ram 2500/3500 |
| 1998.5–2002 | 5.9L 24V ISB (VP44) | Ram 2500/3500 |
| 2003–2007 | 5.9L 24V ISB (Common-Rail) | Ram 2500/3500 |
Notes: OE Ram 5.9L coverage 1989–2007. Some industrial B-Series (ISB/QSB) applications use this bushing—always confirm by ESN and connecting-rod design. Wrist-pin bushings typically require pressing and final-size honing by a machine shop.
Often Paired With
- Pistons & Pins: stock or oversize with new circlips
- Reconditioned Connecting Rod Set (small-end honed to spec)
- Engine Rebuild Kits and assembly lube
What’s In The Box
- (1) Genuine Cummins Wrist Pin Bushing (4891178)
- Sold individually; order 6 for a complete engine set
Install Tips
- Press bushing into rod small-end; hone to final size to achieve correct wrist-pin clearance.
- Align oil feed hole and chamfer per service manual.
- Measure pin/bushing clearance on all six rods; replace circlips and verify pin float.
FAQ
HOW MANY BUSHINGS DO I NEED FOR A 5.9L CUMMINS?One per cylinder—6 total for the inline-six 5.9L. Sold individually so you can order the exact quantity needed.
DOES THIS FIT 6.7L CUMMINS?Automotive coverage is **1989–2007 5.9L**. Some industrial ISB/QSB 6.7 rods use different bushings—verify by ESN and rod part number.
IS MACHINING REQUIRED?Yes—after pressing, the bushing must be honed to size to achieve proper wrist-pin clearance and alignment.
WHAT ARE THE COMMON CROSS-REFERENCES?Popular interchange numbers include 3901085 and 3941476 (verify dimensions against your rod/pin).
IS THIS A GENUINE CUMMINS PART?Yes—OE Cummins 4891178 bushing for dependable fit and durability.
