While driving, if I take my foot off the accelerator, my 2014 jk makes a hissing noise from underneath. Sounds like it’s near the trans. If I’m driving and put it in neutral or press back down on the accelerator , the noise also goes away
Any thoughts???

 

Not certain this applies to the 3.6L motors, but on the 3.8s there is a heat shield on the exhaust crossover that runs under the transmission. It's held in place by several short welds. When one of the welds breaks, that segment of the shield can vibrate, making a very noticeable noise in the passenger compartment. Easily checked to see if that's the problem, Just crawl under and look up to locate the shield and check the welds that hold it in place for cracks. It's quite thin metal, so welding it back in place is tricky. You could place something thin between the shield and the crossover temporarily to test if that's the source of your noise. But it's hot--don't use something that could catch on fire!

 

Thank you for the response. The heat shield is fine, no issue.
The hissing noise happens while I’m driving and let my foot off the accelerator. I can also make the noise stop by putting into neutral.
Any other thoughts would be helpful