42RE, 42RH, 46RE, 46RH, 47RE, 47RH, 48RE, A727, A904 4-Spool Switch Valve Bore wear toward the spring end of the 4-spool switch valve reduces converter release oil in listed Chrysler units. 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. Salvage worn bores with Sonnax 4-spool switch valve 22771A-01. For bores with excessive wear, Sonnax also offers oversized 4spool switch valve 22771A-13. 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