Frank, the dampers are not causing the cracks when acting as dampers, only when acting as anti-tramps.
When the power is on and the propshaft puts the torque into the pinion, the crownwheel turns the halfshafts, together in the case of an LSD. With grip at the tyres, the axle casing will rotate backwards with equal and opposite force while ever there is equilibrium as the car accelerates. If traction breaks there will be a sharp rocking effect between power on and slip, and the part which controls most of the movement - these brackets, will be violently flexed.
That's whats going on. It would be less of a problem with no LSD.
I don't have a LSD and this is my collection of broken bits..........and it's a Plus 4 that's doing it.
