On my 08 63AMG W164 tailgate handle was getting stuck almost every time. And i do see a lot of people have that same problem, they go buy new one or used one on Ebay.
Took mine off, Took the whole thing apart. there is a retaining ring holding it in place, kinda pain in the neck to take that ring off but i used a knife blade and it came off.
Will attach picture. Green is where reining ring is holding that shaft in place. Marked with red where it needed to be cleaned and greased.
Make sure you bend that retaining ring back when you put it back so it will stay in place.
Nothing complicated really, anyone can do it. The biggest pain in the neck was the retaining ring to take off and put the lift-gate panel back.
It Works better than new right now! There is no point to buy new or Ebay used that might have the same problem. If you can fix yours.
Hope it will help many people, thanks!

 

Good show.