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Cummins 4003950 is the engine oil pump with cast body, drive gear and O-ring seals. It is used on Cummins M11, L10 and ISM engines. This aftermarket version is made to the same mounting and connections as the original, so it fits where the old one came off.
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 4003950 |
| Type | Gear type engine oil pump |
| Fits | Cummins M11, L10 and ISM 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 |
|---|---|
| 4003950(SPM-HEP-4212) | Cummins M11, L10 and ISM engines |
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 |
|---|---|---|
| eBay (5 aftermarket sellers) | USD 185.57 to 226.50 | 25 Oct 2026 |
| FridayParts | USD 208.95 | 24 Oct 2026 |
| HDKits | USD 259.00 | 24 Oct 2026 |
| Highway and Heavy Parts | USD 296.45 | 24 Oct 2026 |
| Amazon (RAREELECTRICAL) | USD 380.58 | 24 Oct 2026 |
| Spare Part Mart | USD 167.16 | Today |
Our price of USD 167.16 is 10% to 56% 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.
No. It is an aftermarket part made to fit in place of Cummins 4003950. It is not made by or affiliated with Cummins; the Cummins part number is used only to show what it replaces.
It fits Cummins M11, L10 and ISM engines. Machines change parts between serial number ranges, so check the number on your old part or in your parts manual.
It is made to the same mounting and connections as the original part. Fit new gaskets and seals where they are used, and check for leaks and correct operation before putting the machine back to work.
Yes, we ship worldwide. Shipping is calculated at checkout, and every order is covered by our 30 day money back guarantee and price beat guarantee.
Prices depend on your ZIP or postcode.
Live rates for the quantity selected, delivered to your door. Confirmed at checkout.
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Join Marty Mates and we put 200 points on your account, worth $10 off an order over $75 USD. Then a point for every dollar you spend after that.
No password: you enter your email, we send a code, and that is you in.
