have not seen it so can't answer. Asked that question on this board when viewing a pro built expo camper (company that sells them... cant recall which one though) of one of these trucks where you could see the air cleaner down way low in a video. Spiked my curiosity. For some odd reason I just remembered 939 as to where it came from. Think it was also brought up in another thread on her about air cleaners and who made them. Good bit of info. Catalogs available online etc.