o2pilot,

I just changed ATF in my 300Sd last week. I could see the TC plug while turning the engine with a socket wrench on the crankshaft nut.

Drain the transmission by loosening the filler tube banjo connection first. That will get the pan about 1/2 empty and you will spill less when you remove the pan. There will still be ATF fluid dripping from the filter after you remove the pan so put something under it to catch the fluid.

You don't have to remove brake or put transmission in neutral. Its not the TC that is hard to rotate, its the engine causing the resistance to turning. Best to use crankshaft nut and socket wrench to turn. You need 27mm or 1 1/16 socket and a 5mm allen wrench.

P E H