Bore wear toward the spring end reduces converter release oil. This affects converter charge at idle, causing engine stumble, loss of lube oil flow, overheating and poor performance. Bore wear at the inboard end creates poor TCC apply or a reduction in line pressure boost. Switch valve bores with excessive wear can now be repaired with Sonnax oversized switch valve 22771A-13. If the bore is not excessively worn, install Sonnax standard OE-size switch valve kit 22771A-01. Both the oversized and standard size Sonnax valves will improve the timing and flow to the apply and release circuits.

• Valve controls TCC release oil venting during apply for a firmer apply and no shudder.
• Stem length, spool spacing and exhaust timing have been improved to ensure quicker stroke and less valve bounce.
• Salvages worn bores.