Dana 18 Stuck Fill Plug

So I've been planning on changing the oil in my transfer case and figured I'd start by opening the fill port to feel for the oil level. The only problem is that the fill plug seems to be stuck in place. I've hit it with PB Blaster, tapped on it with a hammer, and gently wrenched on it. My next thought was to use my breaker bar and a socket, although I wasn't able to find a socket that fit very well. I've been nervous to go after it too much, for fear of stripping the bolt. Any other tips? Heat? Impact ratchet?

 

Isn’t the fill port an NPT fitting that you use either a pipe wrench or Allen key depending on the type of plug?

 

went out and checked
9/16 inch 8 point socket 1/2 inch drive
but not sure if you would be-able to get a 1/2 inch breaker bar on it . near edge of frame
I always used a big crescent wrench . yep drain plug is 3/8 square allen plug

 

Impact driver - Wikipedia

 

I bought a set of 12 point sockets just for this. 1/2" drive ratchet.

 

The plugs are tapered pipe threads. The threads actually tighten into each other (plug/case) to form a seal. A hand impact isn't a good choice for pipe threads. A long breaker bar with an appropriate square or 8 pt socket is best.
-Donny

 

I have a set of double square ,or whatever, sockets just for this. It may be very tight, but you won't break it. They are just pipe thread as stated above.

 

Thanks all! None of my local hardware stores have 8 point sockets, so I've ordered one. I'm assuming that the plugs on my T90 are the same size as well?

 

I don’t think I’ve ever used anything but a big adjustable wrench on them.

 

I know I haven't, unless they were a sunken head plug that uses an allen wrench.

 

Same here - He just needs a bigger one.

 

or already used a pipe wrench . on and off

 

Like the one on the right in the photo

 

might try a metric socket to get a good tight fit also 16mm?