Hello,

If you can not find any tool, I suggest you welding a nut into a bolt and use an wrench. It is easier than find te required tool. Those hex tools are quite big, you will need a 14mm for the fill plug, and 17mm for the drain plug.
When I did this on my 270.000 miles Xfire, I filled it with Febi 75w, very important fill it with MB 235.10 GL4 oil.
In my case, I used Febi Bilstein. According to R170 service manual by Mercedes Benz, 75w85 should be used, with 1,5 liters. I filled with about 2 liters because at 1,5 gears weren´t smooth enough.