Product Description
If your 1989-2002 Ram or B-Series engine built with the 5.9 L (12-valve or 24-valve) needs reliable lubrication, then this genuine Cummins 4939587 oil pump is exactly the trustworthy direct-fit component you want.
Manufactured by Cummins to full factory specification, this OEM oil pump ensures proper oil circulation, consistent pressure, and oil delivery across bearings, camshaft, turbocharger and other critical internals — restoring or maintaining longevity and performance.
Whether you’re doing a rebuild, correcting low hot-idle oil pressure, or simply replacing a high-mileage pump, installing this genuine unit helps you return your engine to the dependable performance you expect.
Fitment Details
- Fits Dodge/Ram 2500/3500 with 5.9 L Cummins 12-valve (1989-1998) and 24-valve VP44 (1998.5-2002) engines.
- Also used in many B-Series 4BT, 6BT industrial/off-highway applications where the 5.9L B-Series architecture is applied.
- One pump required per engine; ensure oil pickup tube, oil pan, and cover gasket are inspected and replaced if worn during service.
Why Choose This OEM Pump?
- Direct-fit replacement for Cummins 4939587 – no modification required.
- Restores factory volume & pressure of lubrication system; reduces risk of engine wear/damage.
- Backed by Cummins quality, engineered for heavy-duty use in towing, work-horse trucks, and industrial service.
Cross-Reference / Alternatives
While this is the genuine Cummins unit, you may also want to consider related service parts if you’re doing a front-end or oil system rebuild:
- CUMMINS 3928455 OEM OIL PICKUP TUBE – 5.9L (1994-2002)
- CUMMINS 4089093 OEM ENGINE OIL PAN – 5.9L (1994-2002)
- CUMMINS 3957544 OEM ENGINE OIL COOLER – 5.9L (1989-2002)
FAQ
Will this pump fit my 2003-2007 Ram 5.9L or 6.7L Cummins?
No — this pump is specifically for the 1989-2002 5.9L (12-valve & 24-valve) B-Series engines and commonly used 4BT/6BT applications. The 2003+ common-rail 5.9L/6.7L engines use a different design.
How do I know my oil pump needs replacing?
Signs include low oil pressure at hot-idle even with the correct viscosity oil, presence of metallic debris in oil, or excessive end-play/wear when front cover is removed.
Is this a genuine Cummins part?
Yes — this is the OEM Cummins part number 4939587, manufactured by Cummins for the B-Series engines.
| Specifications for CUMMINS 4939587 | |
|---|---|
| Part Number | 4939587 |
| Brand | Cummins |
| Application | 5.9L Cummins B-Series (12-valve & 24-valve) and 4BT/6BT industrial (1989-2002) |
| Contents | One gear-type lubricating oil pump assembly |
| GTIN | – (Not publicly listed) |
| UPC | – (Not publicly listed) |
| E-Codes / Emissions | Not applicable |
| Shipping Info | Shipment weight approx 4.9 lbs (per Cummins site) |
| Prop 65 Warning | WARNING: This product can expose you to chemicals known to the State of California to cause cancer, birth defects or other reproductive harm. For more info visit P65Warnings.ca.gov |
| Cross Reference | 3901175, 3906414, 3914006, 3914008, 3918212, 3924720, 3926203, 3937404, 3941742, 3930337 |
