to post on above comment about gm aluminum driveshafts. i have a buddy that has a chipped 08 duramax and he sheered his aluminum driveshaft pulling an eliminator. sheered the u-joint on the driveshaft clean off. but probably wouldnt have happened if he wasnt pulling it lol.

 

In my experience with driveshafts and torque, and i have literally tested hundreds to the point of destruction, is that the u-joints will let go way before u have any driveshaft issues....assuming the driveshaft itself is in good condition, no dings exc.

Usually when u see a undamaged driveshaft twist under load, or the ears get sheared off, its still due to the u-joints letting go first, then the bind/shock/weird angles under full load proceed to mangle the shaft.