DUAL-RATIO BOOST VALVE KIT (A340E/A340F)
# 76783K

Dual-Ratio Boost Valve Kit

DUAL-RATIO BOOST VALVE KIT (A340E/A340F)

Fits '00-later V6 & V8, late-style, Type 3 & 4 valve bodies.

Symptoms:

  • Delayed Reverse
  • Delayed Forward
  • Soft upshifts
  • Low pressure

Cause:
Wear of the boost valve sleeve allows leakage and cross leakage of the Reverse, EPC and Cutback circuits.

Correction:
This patent pending Sonnax boost valve kit restores the hydraulic integrity of the circuits and replaces all three OE ratios.


In Toyota/Lexus A340E & A340F late-style units the OE steel cutback/EPC and reverse boost valves wear the inside diameters of the cast aluminum boost sleeve due to continuous reciprocation as they provide biasing force to adjust main line pressure. This wear allows critical Reverse, EPC and Cutback fluid pressures to leak or cross leak, creating numerous drivability complaints and part failures.

Replacing the OE assembly requires matching the correct valve spool ratio (three-dot, two-dot or no-dot sleeve) to ensure proper line pressure. The Sonnax dual-ratio boost valve kit not only restores hydraulic integrity, but also provides for all OE ratios in one assembly. By selecting either the large diameter priority or small diameter priority EPC boost valve and adding optional shims to the OE pressure regulator valve spring face, all three of the OE ratios can be achieved with the one assembly.

  • Sleeve is made from high-quality aluminum for wear resistance
  • Valve is hardcoat anodized to reduce wear
  • Unique priority diameter design allows for dual ratio in one assembly
  • Additional shims allow for tuning to the third OE ratio

Content:

  • Boost Sleeve
  • Cutback Boost Valve
  • Reverse Boost Valve
  • Shim .032" thick, Selective
  • Shim .015" thick, Selective
  • EPC Boost Valve Small Dia. Priority
  • EPC Boost Valve Large Dia. Priority

SONNAX Installation Instructions

Type of Product: Sundry Parts
Qty Needed:
Years:
Alternative #:
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