Aus, your correct. My point, Cryo doesn't solve why they fail. Perhaps i should have explained myself a little more clearly. Doing Cryo treatment alone on the Crown and pinion wheels will have little, if any effect, as the cause the crown and pinion failure in our differentials goes way beyond the structural strength of the crown and pinion wheels (actual metal properties) themselves. Two keys area's seem to be the point where failure over time will occur. One being the diff collar (crush collar) and the other being the end caps which support the LSD centre. Both matters will result in excessive backlash, and overtime or through excessive abusive will cause failure to crown (more likely) and pinion (less likely) failure. Even then i know of a case where somebody managed to split a differential casing. If these area's are rectified to start with, perhaps we would see less failures. So what i'm trying to say is Cryo Treating may buy you time, much the same as spacers do for driveshafts. Your only fixing a known problem with a bandaid solution.