Trans ?

I went mudding nothing to serious just a bunch of mud holes. Well long story short i broke a spider gear in my rear end and i like totally F'ed up my trans only have park, reverse and 1st gear. I fixed the rear end and now i need a new trans. A friend of a friend wants to sell me his trans. It's a 700R4 completely built rated to 700hp with a 10" converter. He told me he paid $1300 for the trans rebuild and like $600-700 for the converter. He told me he would sell it to me for $1000. I was wondering is this a good deal or what? I know a lil more about manual trans not auto. He also told me it takes some type of special trans fluid that's like $12qt. and the trans and converter take 12qts. So is it a good deal or not? Any help is very appreciated.

I paid $1,100 for a rebuilt 700R4 with a 1 year warranty. (Canadian)
He's probably using synthetic oil, which is why the oil is so expensive.