SONNAX 700R4, 200-4R LARGE REVERSE BOOST VALVE
	Quantity in Basket: none Code: SNX-K77898 Price: $19.85 Shipping Weight: 1.00 pounds
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Vehicles with a 700-R4 & 2004R transmission often have complaints of poor reverse boost or upshifts in manual low. This complaint is generally caused by a worn reverse boost valve sleeve or wear at the pump body. Sonnax now offers the larger (.283") reverse boost valve assembly K77898 .and K77898A "Factory" style without o-rings. The sleeve and valve are made from hardened steel, and tight tolerances are maintained to restore the hydraulic integrity of the assembly. O-rings have also been added to the boost sleeve to seal the reverse boost circuit and prevent leakage from the pump body bore. The sleeve lands have also been lengthened to add better sealing and stabilizing capabilities to prevent future bore wear. Due to the differences in thermal expansion rate of steel and aluminum, when the transmission approaches operating temperature the sleeve is allowed excessive clearance and scrubs the bore. The reverse boost valve spool lands have also been lengthened to aid in maintaining hydraulic integrity.