PG/TH350/400 Front Pump Seal

The COAN PG/TH350/400 Front Pump Seal is a precision plastic seal engineered for automatic transmission front pump applications across three classic transmission platforms: the Powerglide, TH350, and TH400. This component is essential for maintaining proper fluid pressure and preventing leakage at the transmission's front pump assembly, a critical junction where pressurized fluid enters the transmission case. Transmission builders and performance shops rely on OEM-specification pump seals like this one to ensure leak-free operation during both street driving and high-performance applications.

The plastic construction of this front pump seal offers several advantages over alternative materials in this application. Plastic seals provide excellent compatibility with modern automatic transmission fluids while maintaining dimensional stability across the temperature ranges these transmissions experience during normal operation. The compact 5.9 x 0.55 x 6.05-inch dimensions allow for precise installation within the pump housing without requiring modification or shimming. A quality front pump seal prevents costly internal transmission leakage that can result in low pressure conditions, poor shift quality, and accelerated wear on internal clutch packs and friction bands.

This seal is essential for transmission rebuilds, overhauls, and routine maintenance on vehicles running Powerglide, TH350, or TH400 transmissions. Whether you're restoring a classic hot rod, rebuilding a performance street machine, or maintaining a vintage truck, a fresh pump seal ensures the transmission retains full pressure and responds predictably under load. The Powerglide remains popular in drag racing and street applications, while the TH350 and TH400 are foundational choices for muscle cars, trucks, and custom builds seeking proven, cost-effective automatic performance. Replacing the front pump seal during any transmission service prevents future complications and extends transmission service life.