Product Details

Heavy duty .471 inch line pressure boost valve for the GM 200-4R and 700R4 automatic transmissions.

• Part Brand: Sonnax
• Part number: 77917-03K
• Transmission models: 700R4 and 200-4R
• Transmission makes: Buick, Chevrolet, GMC, Oldsmobile, Pontiac
• Boost Valve Diameter: .471 inch.
• Year Range: 1980-1993
• Installation: Installs with transmission in the vehicle.
• Applications: Towing and off-road

The Sonnax .471 inch boost valve is a very popular upgrade for the 700R4 and 2004R automatic overdrive transmission. Made from hardened steel to resist wear, this boost valve with sleeve is a great upgrade. A very common problem with these transmissions is a burned 2-4 band or 3-4 clutch pack. The larger .471 diameter valve and sleeve will boost the line pressure of the transmission in all gears, which increases the holding pressure on the clutches, in relation to your throttle position. This valve will increase shift firmness, life of the transmission, and the horsepower handling capabilities of your transmission.

This high-performance boost valve will work in the following makes and model vehicles:

Buick

• Roadmaster, 1992-1993

Chevrolet

• Astro Van, 1985-1992
• Blazer, 1982-1992
• Camaro, 1982-1993
• Caprice, 1982-1993
• Corvette, 1982-1993
• S10, 1982-1992
• Silverado Truck, 1982-1992
• Suburban, 1982-1992
• Van, 1983-1993

GMC

• Canyon, 2004-2012
• Colorado, 1994-2012
• Envoy - XUV – Denali, 2001-2010
• K1500, Some K2500, 1982-1992
• Safari Van, 1985-1992
• Sierra Truck, 1982-1992
• Syclone 1991-1993
• Typhoon 1991-1993
• Van, 1983-1992

Oldsmobile

• Bravada, 1991-1992
• Custom Cruiser Wagon, 1982-1992

Pontiac

• Firebird & Trans Am, 1983-2002

These transmissions are part of the Turbo-Hydramatic series and are also known as: 700R4, 4L60, 700-R4, TH700-R4, MD8, THM700R4, THM700-R4.

This HD line pressure boost valve and sleeve works in all models and years of this transmission, including: 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, and 1993.