This is an oil pump with number 4003950.  Works with Various models of Cummins engine including , M11, ISM, L10.

Just give us your serial number and we will confirm compatibility with your engine!

OE Replacements: 141296, CUP141296, 4003950, 3401186, 3803330, 3803379, 3883910, 3895756, 4003950, 3820882, 3893935

Upgrade your engine’s performance with this premium replacement oil pump from HDKits, engineered for reliability and long-lasting durability. Manufactured using high-grade materials and precision-machined to meet or exceed OEM specifications, this brand-new pump ensures efficient oil circulation and optimal engine lubrication — with no core return required.

Designed to fit a wide range of Cummins mid-range and heavy-duty diesel engines, this oil pump (part number 4003950) is compatible with the L10, M11, and ISM/QSM engine series. Originally launched in the 1980s, the L10 engine laid the foundation for the advanced M11 platform, known for its balance of power and dependability across on-highway and off-highway use cases. The ISM and QSM series, successors to the M11, feature electronic control systems that enhance fuel efficiency, lower emissions, and boost overall performance. These engines are widely trusted in commercial trucks, construction equipment, and agricultural machinery.

Choose HDKits for quality-tested diesel parts that meet the demands of today’s toughest operating conditions. Whether you’re maintaining fleet reliability or rebuilding a high-performance machine, this oil pump offers the perfect combination of quality, compatibility, and value.