While I was under the hood today preparing my truck for a cross country, 7,000 mile trip I noticed the vacuum pump for the ESOF system had an open port. I am not sure if this is supposed to be open and exposed to fresh air or if there is supposed to be a hose on it which connects to another part of the system and was hoping someone could answer that question for me.

The ESOF/4x4 system works as intended as far as I can tell as I have used it several times over the past year I have owned the truck. This is the reason why it has taken me this long to see the exposed port.

Thanks, my finger is pointing to the vacuum port I am talking about.

 

Perfectly normal.

 

What ^^Roland^^ said.

You're not missing a thing.

All our trucks look just like that.

Pop

 

Outstanding, I was starting to feel overwhelmed a bit after I saw that. I have the axle wrap issue going on (just order parts to fix it today), need to swap my transmission fluid out again and when I saw the port I was under the hood fixing the air gap in the compressor and thought.... what else is going on here that I haven't seen...

Thanks for the quick response fellas.

 

I have a followup question (curiosity always gets the best of me).

Is that port the "exhaust" of the vacuum pump? Or is it an extra vacuum source that is just not utilized?