E320 no kick-down

[seamushk]

My 130,000 mile E320 is suffering from no kick-down most of the time. If I stop and switch off, the kick-down may come back but when I floor the throttle, there's a huge cloud of black smoke. After some more running, only a few miles, I lose the kick-down again. A scanner read out gave 'Torque converter lock-up clutch high power consumption'. The transmission oil has been changed and a new filter installed but the fault has returned. Any suggestions would be appreciated.

 

[kwakdonut]

That doesn't sound good. Unfortunately, am not qualified/experienced enough to give a verdict! Car is going into limp-home mode that's obvious. Is there an obvious power-loss in the higher gears (3rd, 4th etc) too?

 

[seamushk]

E320, no kick-down

Thank you for your interest. There's no loss of power and the transmission is otherwise fine. It's overtaking that is problematical.
The torque converter lock-up clutch is designed to create a mechanical drive instead of the fluid coupling when the car is running at a steady speed; this improves fuel consumption. However, when there is a demand for power, I understand that the clutch should disengage and the system should revert to fluid coupling. It seems as if this isn't happening; the lock-up clutch stays locked up. But what is causing it to stay that way is a mystery and the fix ????

 

[BlackC55]

The TC fault is probably unrealted.

I suspect an engine issue. Put it on a Star diag machine first. Most code readers will not pick up all of the fault codes.

It probably has a lack of power

 

[jeremy 2516]

Can you do manual changes using the selector ?