The OE plastic solenoid snout cracks where it contacts the plunger valve causing oil leaks, while the PWM TCC signal drainback valve becomes loose or melts and blocks the converter apply valve.
Replace the broken solenoid snout with an aluminum snout either with or without a built-in anti-drainback valve.
The plastic OE torque converter clutch solenoid snouts are prone to breakage, causing them to leak oil that should be directed to the converter clutch apply valve. Until now, your only option was to replace the entire OE harness or purchase an aftermarket solenoid and splice it into the existing harness. Sonnax offers TCC solenoid snout 77942-02K that eliminates the need for the damage-prone plastic OE drainback valve in for 4L60-E, 4L65-E, 4L70-E ‘97-later PWM units. Sonnax also offers solenoid snout 77942-01K that allows the OE solenoid in '96-earlier 4L60/E units to be rebuilt to better-than-new condition.