• Code 28, 1744, 1740
  • High line pressure
  • Cracked drum
  • Planetary failure
  • Bushing failure
  • Loss of lube oil
  • No cooler flow during failsafe


Worn casting bores at the pressure regulator and converter regulator valves, and insufficient cooler and converter flow.


Sonnax oversized PR valve restores the balance circuit to correct high line pressure and guards against excess EPC/TV pressure. Sonnax PR valve and converter regulator valve have modifications to properly regulate converter and cooler flow.


Master Kit
Part No. 73840-MK

View Instructions Find a Distributor

The CD4E transmission frequently exhibits such symptoms as lube failure, harsh shifts and line pressure instability as well as a variety of TCC Lockup issues. Sonnax master kit 73840-MK contains both the Regulator Kit 73840-RK and the Bypass Kit 73840-BK to address issues in both areas. See the individual kits for more detail.

Both the Regulator and Bypass Kits require reaming for installation. See options below:

Rearmer kit 73840-RTL is no longer in production but may be available from distributor inventory. F-73840-TL is available for use prior to installation of 73840-RK.

  • 73840-RK
  • 73840-BK

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.

Ford CD4E Valve Body Layout

Ford CD4E Valve Body Layout

  • CD4E, LA4A-EL Master Kit 73840-MK
  • CD4E, LA4A-EL Master Kit 73840-MK