why the confusion about rear diff breather?

regarding rear diff breather mod,
why are there mixed opinions on part numbers?

most people seem to get the plastic pieces, but there's one guy who got smaller metal ones who claims the plastic one is a one-way breather, when you need a two-way.

Meanwhile, somebody else said when they picked up the "bad plastic one-way" vent from the dealership, he blew and sucked in it to verify it is actually two-way, and not a one-way breather with a check valve inside.

On the other side, metal might last longer, but that might not be as important as whether or not the thing is actually 2-way like it probably should be.

Anyone know the answer to this?

Also, what's the best place to mount it? I've seen people use gas cap area, bed cubby (lower), and behind tail light (probably similar height to gas cap but more hidden)

I sure hope the Tacoma already comes with more higher up breathers in the front, or adding them will take more time
(manual trans, transfer case, etc.)
Supposedly it does. I think I saw some breather caps high up in the engine bay for them. Not sure why Toyota would make those high up but not the rear diff since both can see water.

metal, 1/4"

 

Do the 2-way, union and breather. I put mine to my driver side tail light, no drilling.

 

So from what I've heard, with a one way breather, if you dunk your hot rear end in cold water, the air inside contracts, you get negative pressure, and it can suck in water through your seals. With a two way valve it can breath both ways and no water through seals. No idea the validity of that, but it's what I've heard some of the confusion on before.

I used a two way and put it in the bed cubby. If I were to do it again I'd probably put it behind the tail light, drilling the cubby was weirdly a PITA.

 

I put mine in the gas cap area,
that way i can give it a few spins to make sure its still free and breezy every time I get gas.
is that necessary? IDK, but I like doing it

 

It's just that simple. Up, clean and out of the way without drilling cutting etc. Well done.

 

That's what I did also,works great.