NISSAN 12279-06J01 Rear Crankshaft Oil Seal

The genuine NISSAN 12279-06J01 rear crankshaft oil seal (SEAL OIL CR/SFT) ensures a hermetic seal at the transmission end of the crankshaft on legendary TD42 naturally aspirated and turbo diesel engines. Its primary function is to prevent engine oil leaks between the engine block and the transmission clutch housing under crankcase operating pressure and high crankshaft rotational speeds.

Technical Specifications

• Manufacturer: NISSAN OEM
• Part Number: 12279-06J01
• Reference / Superseded Part Number: 1227906J00
• Fitting Position: Crankshaft, rear (transmission / flywheel side)
• Engine Compatibility: 4.2 D (TD42)
• Design: Genuine radial shaft seal manufactured from heat- and oil-resistant elastomer with a precision spring-loaded sealing lip

Vehicle Compatibility

• Nissan Civilian (W41) 4.2 D [1999 - 2015] (SEAL OIL CR/SFT (TD42))
• Nissan Patrol (Y61) 4.2 D [1997 - 2016] (SEAL OIL CR/SFT (TD42))
• Nissan Safari Pick Up (TY61) 4.2 D [1999 - 2012] (SEAL OIL CR/SFT (TD42))

Operational Significance and Failure Symptoms

The rear crankshaft oil seal is a critical structural component; leakage resulting from material fatigue, hardening, or wear can lead to engine oil loss. The most common symptoms of failure include oil leaks at the junction between the engine and transmission, oil drips beneath the vehicle, and, on manual transmission models, oil contamination of the clutch friction disc leading to clutch slip or shudder. Preventive replacement is strongly recommended during clutch replacement or engine disassembly.