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  • Gear ratio & solenoid codes
  • Erratic shifts
  • No 3rd when hot
  • No 4th when hot
  • Shift timing change with temperature


Wear of bore end plugs allowing solenoid feed oil to exhaust.


The Sonnax kit contains O-ringed end plugs to positively seal the bores.

4R44E, 4R55E, 5R44E, 5R55E

O-Ringed End Plug & Checkball Kit
Part No. 37947-13K

View Instructions

The end plugs at the kick downshift control, manual low, and throttle downshift control valves become loose. This allows solenoid feed oil to exhaust and drop below 40-45 psi, which prevents the shift valves from stroking fully. The Sonnax kit 37947-13K contains o-ringed end plugs for these three locations, which positively seal the circuit to prevent oil loss.

  • O-ringed end plugs positively seal the circuit to prevent oil loss.
  • End plugs have threaded ends for ease of installation and removal.
  • Kit contains 4 Torlon® checkballs to replace lost or damaged originals.
  • Kit contains 4 L shaped retainer pins to replace lost originals.
  • Small End Plugs (2)
  • Large End Plug
  • Small O-Rings (5) 1 Extra
  • Large O-Rings (3) 1 Extra
  • Checkballs (4) not shown
  • L Retaining Pins (4) not shown

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 4R/5R44E, 4R/5R55E Valve Body Layout

Ford 4r 5r44e thumb

September 21, 2005

Troubleshooting Tips for the 4R44E & 5R55E

Bob Warnke

Topics: Transmission Ford 4R44E Transmission 4R55E Transmission 5R55E Transmission

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  • 37947 13k