986 Tiptronic Problem

[airfighter]

Hi there from Greece.

I'm a recent owner of a Porsche Boxster 986 2.7L (model 2002) with tiptronic transmission. I have this problem: I stopped the car on a crossroad and the engine stalled. That should happened to a car with automatic transmission. Then I tried to go, the revs went up but the car was slightly moving. It seemed that at a point locked and continued to work normal. But that happened again, and 4th gear light with "D" started to flash. That means that there is a malfunction/failure at the tiptronic. The gear lever in "D" or "M" the car is like to be in neutral position. Revs are going up but no indication of engagement. I had to tow my car back to my garage. I checked the transmission ATF lever and it was ok, but it was totally black (I don't know if that's the normal color. But I don't thing that this car had ever changed trans oil).

I suspect that probably oil filter or any solenoid valve has been stacked, or a sensor (there are many of them) has a problem.

Has anyone any idea about that?

[RFM]

A Tiptronic oil and filter change is a must to start with, black colored transmission oil is in most cases also burned. Let check at the same time the present fault codes.

[airfighter]

I checked the car with my friend's help (he is a professional car electrician) with his OBD II. He has not the full boxster data, only for DME. It gave us two falsies that was written in memory. The one is the 4th gear selection without 4th gear engagement (that may be is logical, from the flashing 4th gear as indication of tiptronic problem), and the other was that there is no signal from input speed sensor for turbine. I assume that this indicates a problem at the transmission input speed sensor (a magnetic pick up that reads the input speed to the transmission, located on the hydraulic control unit inside the transmission).

That's a kind of good news, cause it seems that is not a total transmission failure.

[airfighter]

Finally I had to overhaul the transmission, for about 4000 euros. The problem was a broken vacuum line that opens a valve to let oil to oil cooler. So almost everything inside was burnt.