2001 GMC Sierra leaking tranmission fluid

In november 09 the u-joint in front end broke while on highway. When pulled over noticed transmission fluid pouring out. After getting drive shaft fixed and put new transfer case seal and all put together it is still leaking transmission fluid. Except it is leaking were transfer case and transmission meet now, and it is leaking at a rapid rate. Why is it doing this and how can it be fixed??