Had my C350 TD auto for about a year now. Its the late 2000 model so does'nt have tiptronic transmission.
However, if you're in Drive you can flick it right to 4, pull down to 3,2,1 etc.
My Mrs was driving the other day and I was passenger (which is pretty rare). I noticed that she had flicked the stick over to the right into 4 so I asked her why...
Apparently, shes been driving it like this all the time !!!!! She thought it was easier to stick into drive and then flick right 'out of the way'.
So it looks like shes been driving, probably about 2000-3000 miles in 4 not D !!!!
What it looks like it does is not stick it into 4th gear like a manual but restrict the auto box to changing higher than the gear you manually select. So, basically, fron stop the box will change up when it feels necessary but never changes higher than the gear you selected.
So, the Mrs has been drivingg down the motorway stuck in 4th gear !!! And I was wondering why the fuel consumption was so crap when she drove.
Thing is though the merc does 85-90 quite comfortably in 4th (apart from using higher revs !).
Aanybody want to guess at how much extra fuel is used doing 70 in 4th rather than 5th...
:-)