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  • Delayed Reverse
  • Low line rise in Reverse
  • B2 Brake clutches burned


These complaints can be caused by wear of the reverse boost valve sleeve, allowing line pressure to escape to exhaust.


This Sonnax reverse boost valve kit has upgraded materials and tighter clearances to prevent wear and restore proper hydraulic control.

U660E, U660F

Reverse Boost Valve Kit
Part No. 47740-17K

You need this if... View Instructions

Vehicles with Toyota/Lexus U660E, U660F transmissions may exhibit insufficient line rise in reverse gear, delayed reverse engagement and/or a burned B2 brake. These problems may be caused by continuous oscillation of the steel boost valve within the cast aluminum boost sleeve, creating excessive wear and a path for line pressure to either leak to exhaust or leak to the EPC boost circuit and create high line pressure conditions.

Sonnax reverse boost valve kit 47740-17K has upgraded materials and minimal clearances to prevent wear and restore proper hydraulic control.

  • Sleeve is manufactured from highly wear-resistant billet aluminum to prevent excessive wear
  • Restores proper line rise
  • Valve
  • 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 U660E/F, U760E/F Valve Body Layout

U660ef vbl thumb

December 09, 2013

Toyota/Lexus U660E, U660F, U760E, U760F Identification Guide

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Toyota/Lexus U660E/F Vacuum Test Guide

Topics: Vacuum Test Guides Vacuum Testing Transmission Toyota/Lexus U660F Transmission U660E Transmission

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September 30, 2005

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

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  • 47740 17k
  • 47740 17k main

You need this if...

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

  • 47740 17k test