A few questions for my 77 CJ. The other day I was poking around under the left rear corner, right underneath the taillight, and found what I would assume to be some sort of rollover valve/device/thingee (thingee is a technical term.) Does anyone know what I'm referring to? If so, what are the odds that it still works? If it doesn't work anymore, should I replace it with a new one, or just rip it out? Any advice would be appreciated. Thanks.

77 CJ-7 258 31" MTR's - now...
360, TF727, DANA 300, DANA 44's all sitting in the garage just waiting...