• TCC slip
  • Soft TCC apply
  • Code 1783
  • Code 1741, 1744
  • Overheating
  • Low cooler flow
  • Overheated converter
  • Overheated OD area


Cooler bypass leaking or opening at lower cracking pressure.


Sonnax drop-in cooler bypass valve kit salvages the OE fittings and tube, and maintains cracking pressure at 70–75 psi.

4R100, E4OD

Cooler Bypass Valve Kit
Part No. 36605-02K

Fits '97-later units with either style outboard fitting.

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Sticking of bypass components, spring relaxation or poor ball seat in Ford 4R100 and E4OD units will allow the bypass to open at lower cracking pressure. This reduces TCC apply pressure, cooler flow at the overdrive section and radiator flow responsible for heat transfer. Sonnax cooler bypass valve kit 36605-02K allows the bypass valve assembly to be rebuilt, salvaging the OE fittings and maintains cracking pressure at 70-75 psi.

  • Hardened steel T-valve provides secure checkball seat and adequate bypass flow
  • New spring cracks open at 70–75 psi to provide lube if cooler is blocked or restricted
  • Hardened alloy steel checkball resists damage
  • Seven new O-rings provide positive seal for cooler circuit
  • Drop-in Zip Valve parts install quickly and easily
Learn More About Zip Valve™ Drop-In Repairs
  • T-Valve
  • Spring
  • Checkball
  • Small O-Ring
  • Medium O-Rings (2)
  • Large O-Rings (2)
  • Extra Large O-Rings (2) 1 Extra
  • 4R100, E4OD Cooler Bypass Valve Kit 36605-02K
  • 4R100, E4OD Cooler Bypass Valve Kit 36605-02K