So in my efforts to replace faulty and clean up my vacuum lines on my 1987 300D, I managed to accidentally pull out the vacuum line that goes from the UFO to some part of the transmission (line runs down behind the engine (in between the bulkhead and engine)). And I can't figure out where it goes. Ive gotten under the car and looked around, and I've searched all over the internet. Can anyone tell me what I need to be looking for to hook this thing back up? Thanks in advance!

It goes to the vacuum modulator on the tranny. That is the only vac line going to the tranny. The vac modulator adjusts CW and CCW for crispness of shift.

There’s a vacuum line nipple on the green vacuum modulator.



Your modulator might be a different color but that’s where it’ll be.

While you’re there, check that the black cap fits tightly and isn’t cracked.

Sixto
98 E320s sedan and wagon
02 C320 wagon

Thanks guys!! I found it and got it hooked back up. Mine is solid black but i get the feeling that its just dirty as crap. I'll check that cap and make sure there's nothing wrong with it. Thanks again!