Surprisingly the Ford Transit doesn’t come with a cabin air filter even though there is a place for one. I’m guessing the filter was either left out due to cost or because of performance. Maybe with the filter in there the blower isn’t powerful enough ¯\(°_o)/¯ .
Not to worry, you can just buy a filter and install it yourself. The Baldwin PA30000 is the correct filter and can be bought from Amazon.
Apply pressure to the 2 latches at the rear of the glove box to unhook it and lower it down.
Once the glove box is out of the way just remove the black air filter cover by applying pressure to the latch on the left side.
Once the air filter compartment cover is removed you can see the large hole for the filter.
The air flows from the top to the bottom. The airflow arrows on the filter should be pointing down.
Lightly press the air filter into the compartment.