Here is a what a
New Rear End Vent Tube looks like.
I would unscrew and take out the one that is in there and then give it another test drive.
Its not going to hurt anything without having one screwed into the axle housing on a dry day.
It might be rusted in, so you should spray some Liquid Wrench Penetrating Oil on it and let it soak for awhile.
Worst case, if the threads break off in the housing you may need a easy-out to remove the remaining threads.
Once the hole is open, check with a small wire to ensure the hole is open.
The cap is crimped on to the lower threaded portion.
Group # 5.387 part # 3738462 ventilator
