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  • Low line rise
  • Poor shift timing


The regulator boost valve wears the inside diameter of the boost sleeve.


This replacement pressure regulator boost sleeve is tightly toleranced to restore proper line rise control.

RE4F02A, RL4F02A

Pressure Regulator Boost Sleeve
Part No. 93990

View Instructions

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.

  • Sleeve has been manufactured from high-quality aluminum designed to resist wear.
  • Sleeve has been closely toleranced to obtain the original minimal clearance with the boost valve.

Will also work in some RE4F02A units. Compare sleeve I.D., depth, overall length, OD and feed hole location.

  • 93990 combo
  • 93990