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  • Burnt brake clutches
  • Burnt clutches
  • Converter concerns
  • High line pressure
  • Low line pressure
  • Poor shift quality


These complaints can be caused by continuous oscillation of the valve causing bore wear, allowing valuable line pressure and converter feed pressure to exhaust.


Restore proper hydraulic control by refurbishing the bore and installing an improved and oversized Sonnax pressure regulator valve and new boost assembly to match ratios and OE pressure curves.


Must measure EPC spool.

A340E, A340F

Oversized Pressure Regulator Valve Kit
Part No. 97741-06K

Fits type 3 and 4 valve bodies with .426" dia. EPC valve spool.

You need this if... View Instructions

Toyota A340E/F series transmissions may exhibit multiple line pressure and converter-related problems due to excessive wear in the main pressure regulator bore. Wear at the inboard balance spools allows critical line pressure fluid loss, resulting in excessively high pressure, harsh shifts and reduced cooler/converter flow. Wear at the outboard spools robs converter feed pressure and lowers line pressure, resulting in soft shifts and burnt clutches and brakes. The Sonnax oversized pressure regulator valve kit 97741-06K for type 3 and 4 units allows the bore to be refurbished and the hydraulic integrity restored for proper line pressure in all ranges. The improved and oversized Sonnax pressure regulator valve is also paired with a new and improved boost valve assembly to maintain the correct pressure curves and restore typically worn OE hydraulic clearances at the critical EPC, Reverse and Cutback circuits within the assembly.

  • Sleeve is made from high-quality aluminum to reduce wear
  • Hardcoat anodized aluminum valves combat premature wear
  • Pressure Regulator Valve
  • Pressure Regulator Spring
  • Boost Valve
  • Reverse Boost Valve
  • Boost Sleeve Replaces OE 2-dot boost sleeve

Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.

Toyota/Lexus A340E/F Valve Body Layout

A340e f vbl thumb

January 16, 2014

Toyota A340E/F Identification Guide

Topics: Identification Guides Transmission Toyota/Lexus A340E Transmission A340F Transmission

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August 21, 2013

Toyota A340E/F, '00-Later Vacuum Test Guide

Topics: Vacuum Testing Vacuum Test Guides Transmission Toyota/Lexus A340E Transmission A340F Transmission

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September 30, 2005

Anatomy of a Transmission: Oil Flow in the Pump-PR-Converter-Cooler Lube Circuits

Gregg Nader

Topics: Diagnostics And Theory Transmission

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  • 97741 06k combo
  • 97741 06k

You need this if...

A vacuum test at the ports indicated fails to hold at least 18 in-Hg.

  • 97741 06k test