I've picked away the black stuff and sprayed several times with WD40 but still won't budge. Trying to turn out the pipe going into the T. Any ideas on how to free it up. Doesn't seen to be corroded.

Heat from a decent blowtorch and two large pairs of stilsons.

 

Combined with a decent amount of brute force and ignorance that should shift it.

 

 

The two big hammer approach to start with.  

1 hammer against the T close to the edge and hit the T with a good sharp blow on the opposite side, not too hard initially, moving the first hammer to a different stop for each hit as you work your way around the T. If once around doesn't help hit a little harder but don't over do it. The T looks like malleable iron and you could crack it with too much muscle power. If this fails try some heat, real heat - not the wife / GF hair dryer. 

PS. as Crossy had said, brute force and ignorance can also be effective. 

PS 2. If you can tell the difference between malleable iron or steel, and it's steel hit harder, or heat higher. 

Caution when heating, soldering or welding Galvanized Metal.

Wikipedia Metal fume fever

 

Try to keep the work area well ventilated.

put a lengh of pipe over the end of your stilsons,then put some weight on it and give them a good hard hit on the back of the stilson  with a decent hammer . 

 if you do heat it and end up with METAL FUME FEVER , drink lots of milk, its an antidote for gal poisoning .

2 x 36" stillies will do it, guaranteed.

You can see where the teeth of the pipe-wrench was used to install it so measure those and buy the same sized one? 

35 minutes ago, VocalNeal said:

You can see where the teeth of the pipe-wrench was used to install it

I think those were actually left by the OP in his most recent attempts.

I saw those and thought, "Dayum, that's either very soft metal or that pipe's not going anywhere."

 

I'd be thinking of cutting the pipe an inch shy of the Tee, cutting the pipe out of the Tee then putting in a Union somewhere if it needed to go all back together.

Not having a blow torch or 36" stilsons, the heat from fork handles got things moving.