For this trip, as it's urgent, you may think about capping the vacuum before it enters the interior compartment, and keep everything isolated to the engine bay for correct engine/transmission operation. You'll lose some climate, and door locky type comforts, but easier to track down a leak when you've eliminated those areas.

__________________
1987 300SDL #1, 1987 300SDL #2, 1980 240D, 1982 300SD, 1994 S350, 1990 350SDL, 1991 350SD, 1985 300D, 2005 E320CDI

Gone, but not forgotten: 1981 300SD, 1982 300SD, 1987 300SDL, 1983 300TD, 1980 300CD, 1981 300SD #2, 1987 300D, 1987 300TDT, 1980 300D