NISSAN 31397-51X02 Automatic Transmission Oil Pan Gasket

The genuine Nissan (SKU: 31397-51X02) automatic transmission oil pan gasket is a critical sealing component that ensures a leak-free seal between the automatic transmission oil pan and the transmission housing. This premium-grade component prevents automatic transmission fluid (ATF) leaks, thereby maintaining the required operating pressure within the system and protecting internal transmission components from premature wear and failure caused by insufficient lubrication.

Technical Features and Functions

• Excellent Sealing Performance: Manufactured from a specialized elastomer or rubber-metal composite material resistant to automatic transmission fluid (ATF) and high operating temperatures, ensuring long-term elasticity retention.
• Thermal and Chemical Resistance: Resists extreme temperature fluctuations within the transmission and the chemical effects of transmission fluid, preventing premature aging, hardening, or cracking.
• Precise Fit: Engineered according to original OEM specifications, guaranteeing a perfect fit at bolt holes and sealing surfaces while minimizing assembly stresses.

Signs of Failure and Importance

Over time, the automatic transmission oil pan gasket can degrade due to thermal stress and mechanical fatigue. Common signs of gasket failure include:

• Oil stains or puddles under the vehicle (reddish or brownish transmission fluid).
• Low transmission fluid levels, resulting in delayed shifting, slipping gears, or harsh engagement.
• Moist, oily residue along the edge of the transmission oil pan.

Replacing the gasket is recommended during every transmission fluid and filter service, or as soon as a leak is detected, to prevent severe and costly transmission damage.

OEM / Alternative References

• C139751X90
• 31397-51X02 (Nissan OEM)