I have a 3 month old 2010 glk that performs nicely except on several occasions the transmission will not shift out of 1st gear and the engine revs up to very high rpms upon acceleration Turning the car off and restarting seems to fix the problem. Any insights?

 

How do you know it's 1st gear and say not 2nd?

Are you sure you are not in gear limiting mode when this happens? It would say D1 on MFD. If not, then I'd go to the dealer sounds like electronic issue.

 

Check to see if you accidently moved the shift lever over into manual mode.