snapping universal joints

[Mmo]

first the rearmost U joint, and now the one closer to the transfer case has broken. granted, there's a 454 under the hood, and it was starting on a hill for the first one and under acceleration for the second. some damage to the flanges that attach each end too, but hard to say which came first.
guy at the shop said it could be the lift kit, as the angle down from the transfer case to the rear diff is more. but i don't think so, it all spins freely.

theres a lot of body flex, and i aim to fix that first.

anybody find a correlation between body flexing and drivetrain problems? or any other suggestions???

thanks fellas.