Vehicles with a RL4F02A transmission often have problems with poor shift timing and poor line rise. This can be caused by the reciprocating pressure regulator boost valve wearing the inside diameter of the boost sleeve. As this wear increases, pilot/boost pressure, which enters the sleeve, leaks past the valve and exhausts, resulting in poor line rise. The Sonnax replacement pressure regulator boost sleeve 93990 eliminates the above problems.
Will also work in some RE4F02A units. Compare sleeve I.D., depth, overall length, OD and feed hole location.
Contact a Sonnax Parts Distributor.