Cummins 3918999 — Genuine Harmonic Balancer / Tuned Vibration Damper for 5.9L ISB

MPN: 3918999  |  Also Known As: harmonic balancer, crankshaft damper, vibration damper (dampener)  |  Cross-Refs (ID only): 3915069; Komatsu 6735-31-8120

Genuine Cummins tuned vibration damper engineered to control torsional vibrations and protect the crankshaft, bearings, and accessory drive on late 2nd-gen 5.9L ISB platforms. Direct-fit for 1998.5–2002 5.9L (24-valve VP44). Sold individually (1 per engine).

Features & Benefits

• OE-calibrated rubber isolator between inertia ring and hub for precise harmonic control.
• Direct-fit replacement for 1998.5–2002 5.9L ISB (24V VP44) applications.
• Protects the bottom end by reducing torsional loads on the crankshaft and timing set.
• Quiet, smooth operation vs. worn/bulged dampers that transmit vibration.
• Built to Cummins standards for durability and long service life.

Verified Fitment (Automotive)

Industrial/Medium-Duty: Broad 6B/ISB/QSB usage (bus, vocational truck, equipment). Verify by ESN before ordering.

Specifications

• Type: Tuned vibration damper / harmonic balancer
• OE Part Number: 3918999
• Cross-References (ID): 3915069; Komatsu 6735-31-8120
• Quantity Required: 1 per engine (sold individually)

Often Paired With

• Damper bolt: 3903857 (single-use; replace on install)
• Front crankshaft seal kit (inspect/replace if leaking)
• Serpentine belt (replace if glazed or cracked)

What’s In The Box

• (1) Genuine Cummins Harmonic Balancer / Vibration Damper (3918999)
• Hardware and seals sold separately (see “Often Paired With”).

Installation Tips

• Mark belt routing and verify pulley alignment before removal.
• Inspect the old damper for bulging, cracks, or rubber separation.
• Always use a new damper bolt; clean threads and torque to factory spec.
• After start-up, check for runout and abnormal vibration.

FAQ

WILL THIS FIT MY 1998.5–2002 5.9L CUMMINS RAM?

Yes—3918999 is the OE harmonic balancer for late 2nd-gen 5.9L 24-valve (VP44) Ram 2500/3500. Confirm by VIN/ESN if unsure.

IS THIS THE SAME AS 3915069?

3915069 is commonly listed as an alternate/cross number for the same 98.5–02 5.9L application. Order by ESN when possible.

DO I NEED A NEW BOLT?

Yes. The damper bolt is single-use. Replace with Cummins 3903857 and torque to spec.

WHAT ARE SIGNS MY DAMPER HAS FAILED?

Bulging or extruded rubber, wobble/runout, increased vibration, belt noise, or unexplained crank sensor faults.

IS THIS A GENUINE CUMMINS PART?

Yes—OE Cummins 3918999 for proper fit and durability.