blew up 2nd gear

[pauleyman]

I'm helping @ileagleracing rebuild a trans that was just blown up. I've seen stripped 3rd, broken spiders etc but this is a new one on me. I haven't counted teeth yet but I was told this is a jacks trans with some evo3 internals. How much of an evo3 I haven't determined yet. This unit has a 4 spider in it with a modified stock cross and an LSD front diff. I'll wait for Sam to confirm exactly which unit. The trans stripped 2nd gear off the input shaft. Sadly the shrapnel also chipped a few teeth on the center diff. The intermediate looks ok. I'll cleanup all the metal shrapnel and take the rest apart.

I'm just wondering why 2nd gear? This isn't one I've heard of especially on a car that doesn't have a huge turbo. From my understanding it's a v1 hta68 car with lots of supporting mods and about 25psi? Dyno somewhere a little north of 300. This doesn't seem like enough to break 2nd. I'm sure there are a lot of shock loads but still. This isn't a daily driven car. Only autocross events on this trans and I don't think that many in the grand scheme of things. Just to make sure I am verifyiing every gear in teh final drive, tcase etc to make sure there is nothing mismatched although I don't think there is given all the discussion I've had with Sam.

Comments?
We have a 2nd unit to donate parts and build another unit but I'd rather not see this again.

 

[bastarddsm]

That's an oddity for sure. I've only had 1 second get damaged, and it was shrapnel that did it.

 

[We're on Boost]

2nd gear is what broke in mine. I don't know why though. I mean "first cause". I never had anybody take it apart after to look inside.
That was at about 550 hp in street use only and not driven very often. But 2nd gear pulls were mostly what I did for fun with the car. That all was in 2016, 17, 18, 19.
Autocross would use 2nd gear mostly, and possibly with a lot of thrust reversals.