• Soft & inconsistent shift feel
  • Various concerns depending on location of leaking end plug


Worn, damaged and deformed end plugs allow loss of critical hydraulic pressure.


Sonnax O-ringed end plug kit reduces or eliminates leakage at the bore plug.

5R55S, 5R55W

O-Ringed End Plug Kit
Part No. 56947J-66K

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In Ford 5R55W and 5R55S valve bodies, some end plugs and their bores are often worn due to small movements of the end plug within the bore. This motion is caused by continuous rapid fluctuations of fluid pressure, impact of a valve against the end plug face and spring forces where the end plug face is utilized as a spring seat. Additionally, the bore surface and end plugs can erode over time due to high pressure fluid squeezing between the bore and end plug. Sonnax O-ringed end plug kit 56947J-66K helps restore correct circuit pressures by replacing worn OE end plugs. The O-rings provide additional sealing to help prevent hydraulic losses in eroded bores.

  • Restores proper end plug fit in OE bore
  • O-Rings help reduce or eliminate leakage in eroded and worn OE bores
  • Drop-in Zip Valve parts install quickly and easily
Bore Location Single O-Ring Double O-Ring
Coast Clutch Control X
VFS2 Modulator Control X
Intermediate Control X
Reverse Pressure Modulator X
Reverse Engagement X
VFS1 Modulator Control X
Forward Engagement Control X
Intermediate Servo Select X
Rear Servo Control X
Learn More About Zip Valve™ Drop-In Repairs
  • Single O-Ringed End Plugs (5)
  • Double O-Ringed End Plugs (4)
  • O-Rings (15) 6 Extra

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 5R55S, 5R55W Valve Body Layout

Ford 5R55S, 5R55W Valve Body Layout
  • 5R55S, 5R55W O-Ringed End Plug Kit 56947J-66K
  • 5R55S, 5R55W O-Ringed End Plug Kit 56947J-66K