Symptoms:

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

Cause:

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

Correction:

Sonnax drop-in O-ringed end plug and checkball kit positively seals the bores.

4R44E, 4R55E, 5R44E, 5R55E

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

View Instructions Find a Distributor

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. Sonnax O-ringed end plug and checkball 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
  • Drop-in Zip Valve parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs
  • End Plugs (2) Small
  • End Plug Large
  • O-Rings (5) Small, 1 Extra
  • O-Rings (3) Large, 1 Extra
  • Checkballs (4)
  • L Retaining Pins (4)
  • 4R44E, 4R55E, 5R44E, 5R55E O-Ringed End Plug & Checkball Kit 37947-13K
  • 4R44E, 4R55E, 5R44E, 5R55E O-Ringed End Plug & Checkball Kit 37947-13K