Canadian Cryogenic/Ultrasonic treatment

[dguy]

Now all I need is for the replacement gear set to come in, because one out of the four in the set I have now is untrustworthy.  (more on that later)

Meet the untrustworthy gear...  It's the only one out of the set which has any visible damage; roughly 2/3 of the teeth have this condition, only on one face.  Every other aspect of this transaxle is clean & tight, including the gears which interfaced with the damaged one.  There was a small amount of fine (and I mean fine) metallic dust stuck to a magnet near the bottom of the differential housing, but nothing scary.

Oh and of course I found an orphaned VSS driven gear in there.   

In any case, the replacement spider & side gear set arrived Friday, and was shipped out to the cryo shop on Saturday evening.   

[dguy]

The gears came back last Thursday...

A whole $25 (plus shipping in each direction) to have all four treated.

For those interested in the process, they were lowered from room temperature to -185°C over a period of roughly 11 hours, held at that temp for 24 hours, and brought back up to room temperature over the next 24 hours.  After that, they were further tempered at 177°C for two hours; heat-up and cool-down deltas were 75°C/hr for the tempering.

If I had been thinking, I would have photographed the treated gears next to a set of untreated gears.  Their original machined steel grey has become a dark bronze.