sonnax-black Facebook-color LinkedIn-color maillink printlink r_and_r_only SERVOFIX-logo-web Twitter-color VBFIX-logo-web video-logo-web warranty_only Youtube-color


  • 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.


This kit replaces worn or deformed OE end plugs. The added O-rings greatly reduce or eliminate leakage where the bore is worn at the end plug.

5R55S, 5R55W

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

View Instructions

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
Bore LocationSingle O-RingDouble 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
  • Single O-Ringed End Plugs (5)
  • Double O-Ringed End Plugs (4)
  • O-Rings (15) 6 Extra
  • 56947j 66k