RAJOD, I wondered about that as well. My only thought is that perhaps if you face the vent forward, then when you are driving at speed, the air will rush into the vent and create a positive pressure inside the diff, thereby making the problem that you're trying to solve even worse. Don't know if this is actually the case, but it's the only thing I could think of.

 

I did a make shift breather cap. I have the official one on order but won't be here in time so I stopped by a local auto parts store and picked up a few items.

- Rubber gas hose
- fuel filter

I cut the top off the breather (no pressure build up) only a short drive to store.
I tried to blow air through the old breather and could not. Its got a super tiny filter at the end, did not looked clogged just a poor design.

The fuel filter I put on I could easily blow air though it from either end.

Its probably all one needs, I can't see how the official one would be much better. Maybe if I put a elbow on the top it would prevent any rain water from splashing in the opening. Doubt it will even get much in it.

 

Dealer tech I use told me they do not do the update breather, drain fill till it comes out like any other diff, unplug vent from diff blow air in it to be sure not clogged

 

You can put the new one on faster and easier than trying to blow air up from under the truck from the differential side.

The factory cap is so small I would doubt they could get much air out of it.
Its preclogged from the get go. Its built to fail.

How do they do it? Have one guy put his ear to the end inside the engine while another fellow puts a air compressor tip in the fill hole?

The tube is hard plastic, there is no give to it, it would not be easy to pull off the differential without breaking. So if they do check its via the fill hole.