Yes I will. Looks like 3rd gear failed to me and debris took out the rest..
This will be my last post in this thread.
Jed,
If that was the case, we would typically see larger chunks of material broken off of the other gears, as well as heavy impressions in the gear tooth face from the bits of broken gear that have been crushed between the gears. Pictures are attached showing a UTV gearbox currently here with this exact type of damage to the other gears from a gear failure. The UTV boxes are quite prone to this type of damage due to high gear being at the top of stack of gears, and all of the little bits and pieces fall through the lower gears resulting in this type of damage.
This is not the first time we have seen this sort of failure in your gearbox. This is usually caused by oil that has either broken down, usually from excessive heat (300ºF+) for an extended period of time, or from an oil that does not have the proper extreme pressure additive requirements, or from a simply not enough oil in the gearbox.
The pictures of your gears clearly show that there was some level of oiling issue. Since we don't have all of the proper data required to know exactly what that oiling issues was, all we can do is rely on our experience of seeing thousands of gearboxes throughout the past 30 years to rule out all other possibilities.
We have seen single gear failures (a few from the big powered cars) where 3rd gear is quite literally stripped from the shaft and ground smooth, but no other gear was damaged in the process. The chunk of gear tooth that is missing from your 3rd gear was most likely caused by excessive heat due to the excessive friction from the lubrication issue, which de-tempered the material and made it brittle.
If the argument wants to be made that this was a bad batch of gears, keep in mind that each one of the gears in these gearboxes is made in separate batches per ratio, usually 15-25 pieces at a time. Each ratio is heat treated in its own batch at different times throughout the year. There are (9) separate gears in a 5-speed Albins transaxle, and all have been heat treated in their own batches as they are produced. The likelihood of an entire 1st-5th set of gears receiving a bad heat treat in (9) different batches is extremely unlikely, and we would be seeing the same failure in the 15-25 transaxles that have these gears installed.