Cummins 4089742 — Genuine Vacuum Pump Reseal Kit for 5.9L Cummins

MPN: 4089742  |  Also Known As: vacuum pump seal kit, vacuum/power steering shaft seal kit  |  Purpose: Reseals the joint and shaft seals on the engine-mounted vacuum pump to stop oil leaks between the vacuum pump and power steering pump.

Fix that common oil leak on your 2nd Gen. This genuine Cummins reseal kit includes the critical seals and gasket to refresh the vacuum pump assembly on 1994–2002 Ram 2500/3500 5.9L. One kit services one truck.

Features & Benefits

• Direct-fit OE solution for the factory vacuum pump used on 5.9L B-Series.
• Stops leaks at the vacuum pump shaft and pump-to-PS interface.
• Complete reseal contents: shaft seal, O-rings, and interface gasket.
• Cost-effective versus replacing the entire vacuum pump.
• Genuine Cummins materials for long service life.

Verified Fitment (Automotive)

Earlier intercooled trucks (1991.5–1993): Many sources list this kit for 1991.5–1993 12-valve applications as well. Confirm by VIN/ESN or pump tag on early trucks due to running changes.

Specifications

• Type: Vacuum pump reseal (seal & gasket kit)
• OE Part Number: 4089742
• Typical Contents: (1) shaft seal, (2) O-rings, (1) pump interface gasket
• Quantity Required: 1 kit per engine

Often Paired With

• Power steering pump service (hoses/fluid) while the assembly is off the engine
• Vacuum lines/check valves replacement if brittle or leaking

What’s In The Box

• (1) Cummins Vacuum Pump Reseal Kit (4089742) — seals & gasket as listed above

Installation Tips

• Clean mating surfaces thoroughly; a light film of oil on O-rings helps prevent pinching.
• Align the power steering pump to the vacuum pump carefully to avoid damaging the new seal.
• Torque fasteners to factory spec and verify for leaks after warm-up.

FAQ

WILL THIS FIT MY 1994–2002 5.9L CUMMINS RAM?

Yes—this OE kit targets 1994–2002 Ram 2500/3500 5.9L applications. One kit services one truck.

DOES IT ALSO FIT 1991.5–1993 INTERCOOLED TRUCKS?

Many catalogs list 1991.5–1993 usage. Because early trucks had running changes, confirm by VIN/ESN or pump tag before ordering.

WHAT’S INCLUDED IN THE KIT?

Typical contents are a shaft seal, two O-rings, and the pump interface gasket needed to reseal the vacuum pump assembly.

WHAT ARE THE SIGNS I NEED THIS KIT?

Oil dripping at the junction of the vacuum pump and power steering pump, or oil seepage from the pump shaft area.

IS THIS A GENUINE CUMMINS PART?

Yes—OE Cummins part number 4089742.