How much do 901 gears weigh?, Cryo cost estimate... Options

[bondo]

I'm considering getting cryo treatment done on my 901 guts before I put it together. Jake said he pays $10 a pound. I'd do both shafts, 2nd through 5th gears, and the ring gear. Just wondering if anyone happens to know roughly how much that weighs.

[bondo]

Well I've heard several theories on how they fail. One is that the shafts are able to flex out in the middle allowing 3rd and 4th to mesh incorrectly. Cryo treatment *may* prevent as much flex in the shafts. Another is simply too much torque on the pinion, causing its teeth to shear off. Then of course there's the bearing issue but I would think you'd get some noise from that before total failure. I'm most worried about the 3rd/4th failure because it would happen at speed, and possibly without warning. The last thing I want is trans lockup at 50 mph on a freeway onramp.

I'm also toying with the idea of a fluid cooling system, but I want to keep things simple. It would be nice to find a way to use the ring gear to pump the fluid through a cooler instead of having to add an electric pump. I'm told that just pointing the vent the wrong way will cause the ring gear to pump the fluid out, so if I design something specifically to do it it might work. Cooling the fluid will probably help bearing life.