There has been some recent concern regarding at least two 4th gens with installed body lifts that have also broken a steering shaft.
The suggestion is that either
a) Incorrect installation of the BL (not loosening the sliding yoke sufficiently)
or
b) Bending of the shaft at the column tube caused by the body lift and resulting angle son the shaft
has caused the shaft to break.
While this is being discussed/investigated further, for everyone's safety I personally would recommend anyone considering the BL wait until a clear picture of the issue is resolved and that secondly anyone with a BL on a 4th gen inspect their shaft (sic) for any sign of failure.
At this stage it seems very hard to identify whether the shaft has any damage that might be an indicator that it might break, and if the BL really has anything to do with the breakage.
The obvious thing is that when the shaft breaks, you loose steering completely Which has happened recently to two 4th gens with a BL.
Regards
Mark