[yoomooman]

its called a transmission extension housing, the part that cracked is the transmission mount flange

 

[yoomooman]

you wont find it in a j/y....they only sell it with the trans...trust me ive tried and no j/y will let one go unless you take the trans too, go to a trans shop or the ford stealership

 

[yoomooman]

remove the t-case, support the trans, remove crossmember, then unbolt housing, not very hard