Symptoms:

  • Erratic line pressure
  • Poor shift quality
  • Burnt clutches
  • Low converter & lube flow
  • Overheating
  • TCC apply & release concerns

Cause:

Continuous oscillation of pressure regulator valve results in excess bore wear, causing erratic line pressure and/or restricting converter feed oil.

Correction:

Recover hydraulic control and renew line pressure performance by reconditioning the bore and installing Sonnax oversized pressure regulator kit.

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

Oversized Pressure Regulator Valve Kit
Part No. 124740-12K


You need this if... View Instructions Find a Distributor

Ford 6F50, 6F55 and first generation GM 6T70, 6T75 transmissions may exhibit multiple line pressure and converter-related problems due to excess wear in the main pressure regulator bore. Wear at the balance spool end allows critical fluid loss, resulting in excess line pressure, harsh shifts and overheating due to reduced cooler/converter flow. Wear at the outboard spool robs converter feed pressure and lowers line pressure, resulting in soft shifts and burnt clutches. After reconditioning the bore, installing Sonnax oversized pressure regulator valve kit 124740-12K will restore hydraulic integrity for proper line pressure control in all ranges.

  • Oversized pressure regulator valve and matched spring restore OE function
  • Extended valve land for better sealing
  • Hardcoat anodized aluminum valve combats premature wear
  • Spring
  • 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 Gen. 1 6T70, 6T75 Valve Body Layout

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

Ford 6F50, 6F55 Valve Body Layout

Ford 6F50, 6F55 Valve Body Layout
  • 6F50, 6F55, 6T70 (Gen. 1), 6T75 (Gen. 1) Oversized Pressure Regulator Valve Kit 124740-12K
  • 6F50, 6F55, 6T70 (Gen. 1), 6T75 (Gen. 1) Oversized Pressure Regulator Valve Kit 124740-12K

You need this if...

Vacuum tests at the ports indicated fail to hold the recommended minimum 14 in-Hg and 18 in-Hg.

6F50, 6F55, 6T70 (Gen. 1), 6T75 (Gen. 1) Oversized Pressure Regulator Valve Kit Vacuum Test Locations