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Cummins 3821579 is the gear driven engine oil pump in a cast iron body, with its drive gear fitted, a mounting foot and the pressure relief housing. It is used on Cummins NT855 and N14 engines. This aftermarket version is made to the same mounting and connections as the original, so it fits where the old one came off.
The same part is also sold as Cummins AR9835, 3042378 and 3609833.
Sold as one unit. Check the number on your old part, or in the parts manual for your machine, before ordering.
| Part Type | Oil Pump |
| Replaces | Cummins 3042378 |
| Engine | Cummins NT855, NTA855, NT855-C, N14, NH220 |
| Drive | Gear |
| Cross references | Cummins AR9835, 3821579, 3609833 |
| Fits | Cummins NT855, NTA855, NT855-C, N14 and NH220 diesel engines |
| Condition | New, aftermarket |
| Stat. HS-Code | 841330 |
| Country of Manufacture | China |
Cummins machines
Check the part number on your old unit before ordering.
| Cummins Part No.(SPM Part No.) | Fits |
|---|---|
| 3042378(SPM-HEP-4729) | Cummins NT855, NTA855, NT855-C, N14 and NH220 diesel engines |
| AR9835(SPM-HEP-4729) | Cummins NT855, NTA855, NT855-C, N14 and NH220 diesel engines |
| Brand | Part No. |
|---|---|
| Cummins | 3042378 |
| Cummins | 3821579 (this page, SPM-HEP-4729) |
| Cummins | 3609833 |
All of these numbers are the same part.
Low oil pressure
A warning light or low gauge reading with the right oil level and a good sender often means a worn oil pump.
Engine rebuilds
Fit a new oil pump whenever the engine is rebuilt or the bearings are changed. Worn gears undo a fresh rebuild.
Noise from the bottom end
Rattles at start-up while the pressure builds are a sign the pump is not priming quickly enough.
Fitting tips
Prime the pump with clean oil, fit new gaskets and O rings, and check the pickup screen before closing up.
We check what other aftermarket sellers charge for this same part. Their prices on the date we checked:
| Seller | Price | Checked |
|---|---|---|
| MyMROmarts | USD 347.92 | 31 Oct 2026 |
| eBay, aftermarket seller | USD 358.96 | 31 Oct 2026 |
| FridayParts | USD 376.95 | 31 Oct 2026 |
| SINOCMP | USD 389.00 | 31 Oct 2026 |
| Fab Heavy | USD 559.99 | 31 Oct 2026 |
| Spare Part Mart | USD 311.20 | Today |
Our price of USD 311.20 is 11% to 44% less than these sellers.
Found this part cheaper somewhere else? Send us the listing and we will beat it by 5% under our Price Beat Guarantee. Every order is also covered by our 30 day money back guarantee.
Yes, it was made for the Cummins NT855, and 4 more listed under compatible equipment. Check the old oil pump is marked 3821579 or one of the cross references, because makers change parts between serial ranges.
On the Cummins NT855, often 5,000 to 10,000 hours with clean fluid, much less with dirt or air in the system. It is usually changed on condition, not by hours.
Leaks from the seal or weep hole, noise or whining, overheating, or falling pressure or flow under load.
Clean them right back to metal and fit the new gasket or O-ring dry, unless the engine manual calls for sealant.
Yes. Fill the pump and its suction line with clean fluid before the first start. Running it dry, even for a few seconds, can score it.
No. It is an aftermarket oil pump made to replace the Cummins 3821579. It is not made by the original manufacturer; the number only shows what it replaces.
Live rates for the quantity selected, delivered to your door. Confirmed at checkout.
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