I have a 320CDi 2002 90000miles. After a mile or so, the gearbox looses drive and engine just revs. When this happens, it is not possible to go up & down the box with the tiptronic function.
I have replaced the gearbox filter, the electrical plug on the gearbox and the electrical connection plate inside the gearbox. Since then I have done 700 Miles without a problem. But the fault has now come back. My Merc specialist and my Main-Dealer mechanic friends have not experienced this problem.
I now have the Valve-body removed and on my kitchen table and am going to try and see if a solenoid is intermittent or maybe a speed sensor.
The original fluid was OK (no particles and not smelling of burning)
Has anyone any idea what may be the Problem please?