So my 2007 GL450 is doing this: the display is stating that I need to "put the truck into park or neutral to start"...but its already in park. It is also coming up with the display: "go to shop without shifting gears" Also at times, the entire display lights up, bells ringing....I pulled over to the side of the road today, put the truck into park, then the bells started ringing and I could not shift the gears into drive or reverse, with the truck running. So I shut it off, and then it would not start, again, getting all the above display warnings....I let it sit for about 20 minutes, then it started and I was able to get home...now it is in the driveway, doing the same thing, it wont start saying I need to put it into park or neutral to start, but its in park and the shifter will not go into any gear, then the bells start again.
If anyone has any ideas what could be wrong I am all ears...thanks. GD

 

Well, took it to my German repair guy...turns out something called the: "Integrated shift module" is bad. Interesting thing about this: You cannot get this part anywhere else but a Mercedes dealer, AND, the dealer has to put it in. Something to do with the mileage programming. Cost:$835.