Cummins 5273412 — Genuine Crankshaft Drive Gear for ISB 5.9L & 6.7L

MPN: 5273412  |  Also Known As: crankshaft gear, timing gear, crank gear  |  Cross-Refs (ID only): Cummins 3949357, 3965389 · Mopar 5086726AB

Genuine Cummins crankshaft drive gear that maintains precise timing between the crankshaft and cam gear on ISB platforms. Direct-fit for 2003–2018 Ram 5.9L/6.7L common-rail and widely used on ISB/QSB industrial applications (verify by ESN). Sold individually (1 per engine).

Features & Benefits

• OE tooth profile & hardness for quiet operation and long service life.
• Correct press-fit design to prevent timing slip under load.
• 36-tooth spur gear for accurate synchronization with the cam gear.
• Drop-in OEM replacement that matches factory timing marks.
• Backed by Cummins for fit, function, and durability.

Verified Fitment (Automotive)

Industrial/Off-Highway: ISB/QSB 4.5/5.9/6.7 (EPA13+ usage noted by Cummins for ISB/QSB 6.7). Always verify by ESN before ordering.

Specifications

• Type: Crankshaft timing gear (spur)
• Tooth Count: 36
• OE Part Number: 5273412
• Cross-References (ID): 3949357, 3965389, Mopar 5086726AB
• Quantity Required: 1 per engine (sold individually)

Often Paired With

• Front crankshaft seal & timing cover gasket (year-specific)
• Woodruff key (inspect/replace if worn)
• Fresh engine oil & filter after repair if debris was present

What’s In The Box

• (1) Genuine Cummins Crankshaft Drive Gear (5273412)

Installation Tips

• Use an appropriate bearing separator/gear puller to remove the old gear; clean the crank snout thoroughly.
• For installation, use thermal expansion (heat gear/cool crank) and align timing marks; ensure the gear seats fully against the crank shoulder.
• Verify gear seating with a feeler gauge and re-check crank/cam timing marks before reassembly.

FAQ

WILL THIS FIT MY 2003–2018 RAM 5.9L/6.7L?

Yes—this is the OE-style crankshaft gear for 2003–2018 Ram 5.9L and 6.7L common-rail applications (confirm by VIN/ESN).

WHAT ARE THE COMMON CROSS-REFERENCES?

Cummins 3949357 & 3965389 and Mopar 5086726AB are typical identifiers that cross-reference to 5273412.

HOW MANY TEETH DOES THIS GEAR HAVE?

36 teeth (spur gear).

DO I NEED SPECIAL TOOLS?

A heavy-duty bearing separator/gear puller is recommended for removal. For installation, follow Cummins procedures; thermal expansion methods are commonly used to press-fit the gear.

IS THIS A GENUINE CUMMINS PART?

Yes—this is an OEM Cummins crankshaft drive gear for proper fit and durability.