The OE design of the control valve allows for smooth apply and control of exhaust release oil. However, if there is any converter or cooler restriction, converter feed is reduced. This allows the valve to stroke prior to lockup command, resulting in premature TCC apply. This can be aggravated by wear at the plunger valve sleeve due to continuous oscillation, allowing the oil pressure needed to hold the control valve in the release position to exhaust instead. The Sonnax assembly includes a redesigned plunger valve assembly and control valve to prevent premature TCC apply. The new control valve has eliminated the controlled release exhaust reaction spool, which often has a worn bore that causes lockup complaints. The plunger valve sleeve has been extended to aid in sealing this circuit. An orifice plug is included to block the controlled release circuit. These changes prevent the control valve from stroking prior to lockup command due to any converter or cooler restrictions, and are designed to result in a short and firmer TCC apply than OE.

• Newly designed valve components prevent premature TCC apply.
• Parts are made from highly wear-resistant aluminum materials.
• Hard-anodized aluminum valve replaces steel OE version for better hydraulic clearance control as fluid temperature changes.
• New plunger valve assembly restores proper hydraulic clearances.
• A new spring is provided to restore proper holding forces with the newly designed parts.
• Salvages castings with wear at the large TCC control valve spool.
• Drop-in-place kit requires no tooling.