Sonnax high RPM checkball capsule 57510-01 is specially calibrated to prevent pressure drops in high RPM GM TH400 and Powerglide racing applications.

Testing has shown that OE checkballs are unreliable above 5500 RPM. At higher speeds the checkballs can unseat, resulting in drop of line pressure or converter pressure. Variables that effect checkball performance include: diameter of ball, mass of ball, distance from centerline, seat angle, oil pressure and RPM.

For racing applications that see RPM above 5500, the checkball in piston or drum should be replaced with Sonnax high RPM checkball capsule 57510-01. This universal part can be installed in TH400 pistons or drums and Powerglide drums with four bleed holes.

• Prevents pressure drop above 5500 RPM
• Upgrades all OE and aftermarket TH400 drums and pistons
• Upgrades OE and aftermarket Powerglide drums with four bleed holes