They're 7/16-20 bolts, so 55-65 ft./lb. will work. Normally, there's a plastic vent with a loose-fitting cap near the top of the case to keep bugs, etc. out of the trans case, or a small piece of steel tubing with a 90-degree bend in it. Unless you're planning to go off-roading and get that part of the transmission case submerged at times, I see no reason to attach anything to the case vent.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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