Gear Housing Gasket Compatible With Cummins 4Bt3.9/6Bt5.9 1984-2002 B Series 5.9L 6-Cyl Diesel Paper

CASE BACKHOE LOADERS:
• Case 580K/580SK/580L 4BT 3.9L Diesel (1987-1999)

CUMMINS POWER UNITS:
• Cummins 4BT3.9/6BT5.9 B Series 3.9L/5.9L Diesel (1984-2002)


IMPORTANT:
This gear housing gasket fits the Cummins B Series — covering both the 4BT 3.9L (4-cyl) and 6BT 5.9L (6-cyl) engines. It seals the timing gear housing to the engine block. The B Series gear housing is on the front of the engine and contains the timing gears, fuel injection pump drive, and oil pump drive. Do NOT confuse with the flywheel housing gasket (rear of engine) — different part entirely.

Failure symptoms: oil seeping from the front timing cover area, oil on the vibration damper or front pulley area. The paper gasket material degrades over time and from oil debris. When replacing, inspect the gear housing for cracks — the cast aluminum housing can crack from overtightening or thermal stress. Also inspect the front crankshaft seal while the cover is off. The B Series was used across a huge range of Case, Dodge, and industrial equipment — always confirm the engine serial number as gasket dimensions changed across production years.

⚠️ Verify B Series engine model (4BT or 6BT) and serial number before ordering.