Originally Posted by PhilM
I'm always super-interested in your contributions.. thanks
but, what does that mean? If it's not controlled, or closed (locked?) what is it doing? Just what it pleases? lol
If that makes sense!
The TCC in the ZF 6HP series is not an on/off lockup, as previous auto gearboxes. It has the ability to be engaged and released in steps, a gradual function to prevent the abrupt feel of an on/off clutch. The TCC solenoid is controlled by pulse width modulation to regulate oil flow and pressure. So when the engine/gearbox is cold the TCC is neither in controlled (step mode) or engaged (closed).