• Line pressure instability
  • Burnt clutches & bands
  • Low EPC pressure
  • Low line pressure


Fluid leaking past OE pressure regulator end plug.


Sonnax drop-in O-ringed plug kit eliminates leakage at the bore plug.


O-Ringed End Plug Kit
Part No. 73840-06

Fits pressure regulator valve bore.

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Ford CD4E and Mazda LA4A-EL transmissions often develop a leaky end plug at the pressure regulator bore causing line pressure instability, low EPC pressure and ultimately resulting in burnt clutches and bands. Replacing the OE end plug with Sonnax O-ringed end plug kit 73840-06 provides a solid seal to halt TV/EPC pressure loss from this circuit. Drop-in Zip Valve parts install quickly and easily.

Learn More About Zip Valve™ Drop-In Repairs

Can be used with OE pressure regulator valve or with Sonnax oversized pressure regulator valve 73840-RK.

  • End Plug
  • O-Ring

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 O-Ringed End Plug Kit 73840-06
  • CD4E, LA4A-EL O-Ringed End Plug Kit 73840-06