Cummins 3937111 — Genuine Front Crankshaft Seal Service Kit for 5.9L Cummins

MPN: 3937111  |  Also Known As: front main seal, crank seal, front crankshaft seal kit  |  Supersedes/Cross-Refs (ID): 3904353, 3900709

Genuine Cummins front crankshaft seal service kit for B-Series 5.9L engines. Restores a leak-free seal at the crank nose and timing cover. Direct-fit for 1989–2007 5.9L Ram 2500/3500. Includes seal and Cummins’ depth/installer components for correct, damage-free installation.

Features & Benefits

• OE sealing material designed for heat, pressure, and vibration in diesel duty.
• Service kit format with installer/depth tools for consistent seating.
• Direct-fit replacement for 5.9L 12-valve and 24-valve applications (non-CR & 2003–2007 CR).
• Helps prevent oil leaks that can foul the damper and accessory drive.
• Backed by Cummins for fit, function, and longevity.

Verified Fitment (Automotive)

Industrial/Off-Highway: Used primarily on Tier-1 5.9L B-Series engines; verify by ESN before ordering.

Specifications

• Type: Front crankshaft main oil seal (service kit)
• OE Part Number: 3937111
• Supersedes/Cross-Refs (ID): 3904353, 3900709
• Includes: Front crank seal and Cummins installer/depth components
• Quantity Required: 1 per engine (sold individually)

Often Paired With

• Install tool: 3824498 (Cummins front seal installation tool)
• Front cover gasket: 3918673 (’94–’02)
• Balancer bolt kit & RTV: Common add-ons during seal service

What’s In The Box

• (1) Genuine Cummins Front Crankshaft Seal Service Kit (3937111) with installer/depth components

Installation Tips

• Clean the crank snout and front cover bore; inspect for grooves. Use the included installer for correct depth.
• Lightly oil the seal lip; do not distort the garter spring. Follow Cummins torque specs.
• If a groove is present on the crank, use a wear-sleeve kit instead of a bare seal.

FAQ

WILL THIS FIT MY 1989–2007 5.9L CUMMINS RAM?

Yes—3937111 is the OE front crank seal service kit for 1989–2007 5.9L (12V, VP44 24V, and 2003–2007 common-rail). Confirm by VIN/ESN.

DOES THE KIT INCLUDE AN INSTALLER?

Yes—the Cummins service kit includes installer/depth components so the seal seats correctly without damage.

WHAT SHOULD I USE FOR A 6.7L (2007.5+)?

Most 6.7L applications use different seals (e.g., 4931561 or 3804899). Check VIN/ESN to be sure.

WHEN SHOULD I REPLACE THE FRONT MAIN SEAL?

Anytime you see oil at the damper/timing cover area, or when the front cover is off for service.

WHAT IF MY CRANK HAS A GROOVE?

Use a wear-sleeve solution (e.g., 3802820) to restore the sealing surface.