Is this thing really needed? Does anyone know and what are the side effects of not having one?? My u-joint broke and the rear drive shaft knocked the evap can clean off. It runs fine now without it. Any advice??

 

It's mostly for hydrocarbon emission control. Evap canister captures the excess fuel vapors in your gas tank and runs them through charcoal, then expels them. It also prevents a vacuum situation in the gas tank.

But it's likely you're venting fuel vapor directly under the chassis, if the hose is just hanging there. If you overfill your tank, it should also pour out there.

 

Mine ran away from home a few months ago. Still running like a champ.

 

Gas cap light has been on since last rock climb. Runs like a champ still. Looked underneath and saw hoses and an electric connector just hanging free in front of the gas tank. Must have had a really good time rock climbing! Just seems strange a rock can grab the vapor canister and not tear out the fuel tank?
Dealer wants $108 for parts ($79 for the can & $22 for the bracket). Autozone does not carry the bracket. Even funnier is license renewal is end of Feb and requires an emission test. Love to work on my 08JKU!