drain ATF to replace governor pressure valve?
 

Does the ATF needs to be drained before replacing the governor pressure valve?

1992 300D, 722.418 tranny.

I would so you dont create a mess

Should I drain both the pan and the converter, or can I just drain the pan?

both

Isn't the fluid flow blocked between the converter and the rest part of the transmission?

When I drained ATF a while ago, the fluid in the converter did not come out though the drain plug opening of the transmission pan. Less than half of the liquid came out of the pan. More than half remained in the converter, and that came out though the drain plug opening on the converter.

I said drain both because most likely you will be replacing the fluid and so you have new fluid in both.

I see. Thank you.

I gave the mechanic 4 quart bottles of ATF, but he took only one bottle.

The invoice states "replace governor pressure valve", but the parts do not seem to be the governor pressure valve (may be because I am not a mechanic):
000-304-28-90 magneto supp
000-304-27-90 coil
115-304-01-60 seal.accel c
001-997-35-48 seal ring, tr
008-997-30-48 seal ring, vl
008-997-31-48 seal ring, vl

Is shift solenoid (kick down solenoid) sometimes called governor pressure valve?

no they arent the same so I would go back and talk to him.

Below is what they said.

The magneto supp and coil that was replaced are part of what is called in Mercedes a Governor pressure valve switch. In modern days, it is also called solenoid.