I am going to replace the vacuum modulator on my 1981 240D vacuum only controlled transmission to see if I can get it to shift again... - I am wondering if anyone has any tips ? I received the new part and it appears that it just screws out and the new one screws back in? Then pop on the top and o-ring, connect the vacuum cable and good to go?

Will I need to drain the trans fluid before doing this - i.e. if i just unscrew the old one will fluid start spewing out of the hole?

here is a photo of the modulator in my car:



Thanks for the help!

__________________
1981 240D ... 265k
1977 240D ... 265k
1977 240D ... 250k