Sonnax Boost Valve Kit

The Sonnax Boost Valve Kit is a drop-in repair for automatic transmission pressure regulator boost circuits. It is also called a boost sleeve and valve kit. It restores line pressure and hydraulic control in worn valve bodies and pump assemblies. Sonnax offers these kits across many transmission families.

The Problem It Solves:

• The hardened steel boost valve moves back and forth inside an aluminum boost sleeve. Over time this wears the sleeve bore.
• The worn sleeve lets oil leak past the valve to exhaust, which can cause low or no line rise.
• Typical symptoms include soft or flared shifts, delayed or harsh reverse engagement, and reverse shudder.
• Left uncorrected, the leakage can lead to clutch or band failure.

Key Features:

• Highly wear-resistant replacement sleeve, made from aluminum or steel depending on the application
• Tight tolerances between valve and sleeve to restore hydraulic integrity
• Many kits have O-ring-sealed sleeves for a positive seal in the casting bore. Factory-style non-O-ring designs are available for other applications.
• Some applications use upgraded boost ratios, springs, or plugs, so firmness and line pressure vary by kit
• Drop-in Zip Valve parts install quickly and easily, so the original valve body can be reused

Sonnax is a respected name in transmission rebuilding, known for correcting common original-equipment wear points. These kits help a rebuilder or technician get long-lasting, reliable shift quality and line pressure.