Automatic gearbox

[alanlloyd]

ML270 cdi
I have experience a lock into 3rd gear, the auto box would not change gear nor could I switch to trip.
After some time over half an hour I stopped the car turned everything off, re-started and everything was fine and since.
Are there any looming problems or anything for me to do?

 

[whitenemesis]

Could be first indications of an electro-plate failing. I had something similar, it could go months without problem, could go again tomorrow!
Best get the fault codes read, possible speed sensor implausible value..