I have a 2017 Pilot and about 20K I started to smell transmission fluid from vents when I didnt have recirculate button on for ac after driving for a bit. Brought it to dealer and they said my fluid was dirty and that I should have changed it at 15k. Never heard this before. They couldnt tell me why I was smelling the fluid. They made up some bs story that there was oil from last oil change which I know was not true because I did oil change at my shop and I know for a fact it was clean and not oil spilled. So they raped me for $350 for transmission fluid change and reprogram of atf. So I still had the smell after that. I made the mistake of not calling honda usa to complain. Now I have 60k on the truck and smell is still there. Drove my dad's 2019 Pilot with 18k on it and it also had that smell. Wondering if anyone else experienced this smell in 3rd generation pilots. The vent setting needs to be set on outside air with heat or ac on.