CUMMINS 3920758 OEM TIMING GEAR CASE HOUSING (GEAR HOUSING) – 5.9L 12-VALVE (1989–1993)

Product Description

The Cummins 3920758 OEM Timing Gear Case Housing is the genuine factory replacement gear housing engineered for the legendary 1989–1993 5.9L 12-Valve Cummins. Designed to restore perfect timing alignment and prevent front-engine oil leakage, this housing delivers long-term durability and reliability.

This OEM housing eliminates the risks associated with worn, cracked, or warped aftermarket cases—ensuring your 12-valve maintains proper camshaft, crankshaft, and injection pump timing. Manufactured to Cummins’ strict tolerances, the 3920758 gear case housing provides leak-free sealing and long-term structural stability even under heavy load or performance use.

FITMENT

• 1989 Dodge Ram 2500/3500 – 5.9L 12-Valve Cummins
• 1990 Dodge Ram 2500/3500 – 5.9L 12-Valve Cummins
• 1991 Dodge Ram 2500/3500 – 5.9L 12-Valve Cummins
• 1992 Dodge Ram 2500/3500 – 5.9L 12-Valve Cummins
• 1993 Dodge Ram 2500/3500 – 5.9L 12-Valve Cummins

CROSS-REFERENCE / RELATED CUMMINS PRODUCTS

• Cummins 3920381 Front Crankshaft Seal Kit (5.9L 12-Valve)
• Cummins 3901093 OEM Camshaft Bushing
• Cummins 3926701 OEM Front Cover Gasket

FAQ

Does this gear housing include seals or gaskets?
No. This part is the bare gear case housing. Gaskets and seals must be purchased separately.

Is this a brand-new Cummins OEM part?
Yes. CPP Diesel only supplies brand-new genuine Cummins components—never reman or aftermarket substitutes.

Will this fit 1994–1998 12-valve engines?
No. The 1994–1998 12-valve uses a different timing gear housing design.

What symptoms indicate a failing gear housing?
Oil leaks at the front engine cover, damaged alignment surfaces, cracked housings, and timing misalignment during rebuilds.

Specifications for cummins 3920758