Tranny housing keeps blowing

[860Yukon]

i have a 96 yukon 4 door with a 6'' suspension lift and a 3'' body lift on 35's, stock gears and electric shift for the t case, the problem is i keep breaking the tranny housing on the back end just before it connects to the t case. ive done it twice. ive been told i need to change the angle of the rear axel, or put a middle piece between the tyranny and transfer case to angle the t case down so its not on such an angle.... any ideas?