Symptoms:

  • Delayed engagement
  • Low line rise
  • Low line pressure in Reverse
  • High line pressure in Reverse
  • Erratic line pressure
  • Soft upshifts
  • Repeated clutch failure

Cause:

Severe wear of the boost sleeve allows TV and boost oil leakage.

Correction:

Sonnax drop-in boost valve kit restores hydraulic integrity and prevents cross-leaks.

Warning:

To ensure correct part is ordered, measure OE valve spools and compare dimensions.

Part Number Large Spool Small Spool
97855-23K .566 dia. .523 dia.
97855-30K .546 dia. .480 dia.

A340, A340E, A340F, A340H

Boost Valve Kit
Part No. 97855-30K

Fits Type 1 units with .546" and .480" dia. spools only.

View Instructions Find a Distributor

The steel OE valve in Toyota/Lexus A340 and A340E/F/H Type 1 transmissions moves within the cast aluminum sleeve, wearing the sleeve. After this wear becomes severe, the valve no longer operates properly, causing soft upshifts and delayed engagement. Sonnax boost valve kit 97855-30K restores hydraulic integrity and prevents cross-leaks.

  • Sleeve is made from high-quality aluminum for better wear resistance
  • Hardcoat anodized aluminum valve combats premature wear
  • Drop-in Zip Valve™ parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs
  • Sleeve
  • Valve
  • Shims (3)

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 A340, A340E/F/H Valve Body Layout

Toyota/Lexus A340, A340E/F/H Valve Body Layout
  • A340, A340E, A340F, A340H Boost Valve Kit 97855-30K
  • A340, A340E, A340F, A340H Boost Valve Kit 97855-30K