06 ML350 Tranny will not return to "Park"
 

With all the tranny issue threads, I thought I would find this problem already presented...no luck...

06 ML 30 97K miles. Tranny has begun to exhibit the issue of not returning the the "Park" "P" position and the button on the gearshift post is pressed. It will not move to reverse "R" either when this problem presentes itself.

I can move between "N" and "P". When the car is turned Off, the selctor moves to P. Upon start up, the car is in P and can be shifted normally. right now it's intermittent.

A service message comes on and states that the vehicle should be taken in for service.

Has anyone else experienced this? If so, very curious what the problem is. I am seeing large sums of cash leaving my bank account.

That Truck uses an electronic system for gear selection.

The part on the trans is called the ISM (intelligent servo mechanism).
Either it is having a problem OR need "re-adapted".

Since it shifts into Park when you shut it off, the ISM is probably OK. It's most likely a faulty "direct select" switch (the one on the steering column). The only way to be sure is to have it checked out by someone equipped with SDS and knows how the ISM/Direct select system works.