He sounds like a dumbass. I can see if he cryo treated a complete assembled transmission, but who the hell would do that?
Cryo treating is a debated topic, as there is no scientific proof that the treatment will change the properties of the metal. The only proven treatment, is hardening and tempering to a specific number. Hardening makes the metal very abrasion resistant (if its a hardenable steel), but also makes it crack, instead of yield. People say that hardening makes it brittle, but thats not the case. The same amount of force that would cause an unhardened metal to yield, is the same amount of force that it would take to crack a hardened piece of metal. It just takes the yield and plasticity range out of the equation.
When you light temper after hardening, you gain back some of the yield, but retain most of the hardening characteristics. Basically, you retain alot of the hardness, but its less "brittle".
Lets say you're starting with A2 tool steel. You harden it, and end up with rockwell hardness 62. You drop the piece on the floor, and it will shatter. If you did a light temper, it would be about Rc 55. Still hard and pretty abrasion resistant, but it wouldnt shatter. There is no proof that cryo treating does any of the above. Many think its a total racket.
