Rear Diff Breather

smell would be my only concern. most people run them to as high point in the engine bay

Agree, I have mine at the highest point in the engine bay. Easy to check and for my purposes high enough. Some people run them even along the snorkel...

I also made an extension to my fueltank breather pipe to run it up into a secure place.

By the way, I like these ARB ones. It is the same sintered metal filter like with the ARB compressors, right?

Cheers, Bjoern
 
high as possible is best...unless your like my buddy.
he puts baby nipples from a bottle over his.
works great as their one way too...but it takes a special kind of man to drive around with nipples on your diffs...
The highest possible point away from potential water is always a good choice. I don't sse an issue with your location except the potential gear oil smell that others have already mentioned. Having them in an easy to check location is handy, and you have that now, so if it works for you I say keep it there. If your interior is floating in water there are probably bigger issues than the breather. I personally like to keep my nipples above water, except when bathing or swimming ;)
 
I have my rear one routed into the gas cap area. Hidden, but not hard to get to. In an enclosed area so very low chance of it getting plugged at all.
 
I've got the accordian style cap on the rear diff relocated just behind the driver tail light in the bed stake pocket, my transmission, t case and front diff are routed to my air box snorkel.

Inside the cabin should work just fine.