Cryo-treating was just discussed in greater detail on pirate. There is nothing wrong with croying DD gears, both front and rear. Cryo'ing them does not make the metal softer, it just rearranges the molecules to reduce stress risers. Heat treated gears (annealing) is what you don't want on a DD in the rear, although it's no problem in the front unless you drive on the freeway in 4wd (
). The heat treating is what makes the metal sof/less brittle to protect from shock damage.
