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  • Loss of lube oil
  • High line pressure with no indication of boost
  • No lockup
  • TCC cycling
  • Overheated converter
  • TCC slip under load
  • No line rise during TCC apply in 4th


Excess boost valve bore wear reduces oil pressure to the switch valve, resulting in a partial stroke position, restricting the converter and lube circuits.


The Sonnax oversized lockup boost valve restores the proper pressures to the switch valve and main regulator valve, ensuring proper flow through the converter and lube circuit and correcting line pressure.

42RE, 42RH, 46RE, 46RH, 47RE, 47RH, 48RE, A727, A904

Oversized Lockup Boost Valve Kit
Part No. 22771-19K

You need this if... View Instructions

Chrysler 42-46-47-48RH/RE transmissions are equipped with a lockup boost valve that is prone to wear. When this valve wears, it causes a loss of converter and lubrication flow, which can result in TCC slip and an overheated converter. Lockup boost valve wear also causes excessive line pressure, and line rise during TCC apply or in 4th gear can be lost. Sonnax offers an oversized lockup valve boost kit, 22771-19K, that restores the lockup boost circuit pressures. The lockup boost valve kit will correct TCC apply, lubrication and overheat problems, as well as maintain proper line pressure.

  • Both valves are hard-coat anodized aluminum to resist wear
  • The Sonnax spring is calibrated to match OE pressure with the oversized valves

Fits 90-later with boost oil delivery tube.

  • Lockup Boost Valve
  • Plug Valve
  • Spring
  • Spring Retainer

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.

Chrysler 42-46-47-48RH/RE Valve Body Layout

42 48rhefamily

November 14, 2016

Chrysler 46RE, 46RH, 47RE, 47RH Vacuum Test Guide

Topics: Vacuum Testing Vacuum Test Guides Transmission Chrysler 46RH Transmission 47RH Transmission 46RE Transmission 47RE 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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  • 22771 19k combo
  • 22771 19k  1

You need this if...

A visual inspection reveals wear, especially at the inboard end and valve plug end. Inspect and vacuum test as shown in illustration.

  • 22771 19k