The vent in the back has slats/gaskets that are supposed to only allow air to escape out from the Jeep and not allow air in. It is there for 2 reasons...1) air brought into the cabin through the HVAC needs to exhaust somewhere; 2) Allows air to escape when you shut the doors with the windows closed. You do not want to have an opening in the rear of the Jeep where gas can come in because the exhaust swirls up around the tailgate at speed and you do not want that CO coming in. If you are going to leave the hatch glass open, crack or open a window so that you have airflow going out.

Paul

Hit the Nail on the Head...lol..Good to see the Knowledge...lol...Most don't think about it but all vehicles have these Exhausters. They are most of the time Hidden because design has them in a certain area. It's like your Home HVAC system where the supply is the exhaust, if it can't blow air out, from blocked registers etc then it can't bring in air (return). The Cowl is the Enter point on Hood and the Tailgate Exhauster is the exit. That's why it's known to not use Recirculation too long because no fresh air brought in.:clap:

This is what I was saying. The keyword to your explanation is supposed to. The wranglers are no more sealed then other vehicles. With drain plugs, tail gate vents and soft tops its easy for gases to enter the cabin. I was just stating that air can still flow in to the rear during normal driving. Like my 07, whose rear vent flaps were all gone. Apparently they just fell apart while under the tire carrier, no telling how long it was like that.

Back to the OP. Depending on the terrain is what I would saw. I've had my jeep for 6 years and when I have the top on, I usually leave the glass up when I'm driving around town. Never had shock issues.

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They are under $20