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  • 1-2 Flare
  • 2nd Slip
  • 5-6 Flare
  • 6th Slip
  • Erratic shift timing
  • No 2nd
  • No 6th
  • Ratio codes
  • 2-6 Clutch burned


Oscillation of the 2-6 clutch regulator valve causes bore wear that prevents proper hydraulic actuation of 2-6 clutches.


Recover hydraulic control and renew shift performance by reconditioning the bore and installing Sonnax oversized 2-6 clutch regulator valve kit.

6F50, 6F55, 6T70 (Gen. 1), 6T75 (Gen. 1)

Oversized 2-6 Clutch Regulator Valve Kit
Part No. 124740-17K

You need this if... View Instructions

2-6 Clutches in Ford 6F50, 6F55 and GM first generation 6T70 and 6T75 units are applied in second and sixth gears in conjunction with other clutch packs. As the 2-6 clutch regulator valve oscillates and strokes over time, bore deterioration results, which prevents proper hydraulic control of the 2-6 clutches. This can cause flares, slipping, erratic clutch apply timing, ratio codes, and burnt 2-6 clutches. Reconditioning the bore and installing Sonnax oversized 2-6 clutch regulator valve kit 124740-17K restores normal shift operation and clutch control by re-establishing the hydraulic integrity of the 2-6 circuit.

Proper operation of 2-6 regulator valve depends on correct AFL pressure being supplied to pressure control solenoid. If problems are found with AFL pressure, Sonnax offers oversized AFL valve 124740-01.

  • New spring matches OE calibration
  • Hardcoat anodized aluminum valve combats premature wear
  • Annular grooves help center valve in bore to reduce future side-load wear
  • Spring
  • Regulator Valve
  • Gain Valve
  • End Plug

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.

GM 6T70 (Gen. 1), 6T75 (Gen. 1) Valve Body Layout

Gm 6t70 6t75 vbl

November 06, 2014

Ford 6F50, 6F55 Vacuum Test Guide

Topics: Vacuum Test Guides Vacuum Testing Transmission Ford 6F55 Transmission 6F50 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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  • 124740 17k combo
  • 124740 17k

You need this if...

Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.

  • 124740 17k test