Automatic Transaxle - ZF 4HP 16 - Service, Overhaul, Removal & Installation, Troubleshooting & Diagnosis: Reverse: Lubrication/Cooling
The lubricating valve ensures that the converter is supplied with cooling oil first if the pump rate is low. The lubricating pressure valve also guarantees that the necessary amount of cooling and lubricating oil is available through the bypass duct.
The fluid which is supplied from the torque converter flows to the cooler through the lubrication valve.