The cast-aluminum cutback valve sleeve in Aisin AW 450-43LE units breaks at the retainer area due to sleeve porosity and the retainer cocking in the bore and exerting excessive force on the thinnest part of the sleeve. This allows the valve and sleeve to move out of position and can create engine stalls when put in gear. It also allows the lockup control valve to move out of position, which can create converter apply issues. Broken pieces of the sleeve can end up in the pan, break into smaller pieces and clog filters or lodge in moving components.

The Sonnax billet aluminum cutback valve kit 94987-01K provides higher tensile strength and reduced porosity to resist breakage.

• Billet aluminum sleeve provides higher tensile strength and eliminates breakage
• Improved valve and sleeve materials prevent wear and provide better sealing capacity through temperature changes
• A replacement spring has also been provided, to maintain OE calibration