Bingo.... we used to do a ton of trs stuff , once a case has seen a blow-up of the lower gears the case gets stretched and the new gears will never last like they did in a new case.. The only real way to make them live is to change the gear sets out before they blow-up and ruin the case..

Are these new gear sets?

Yes new gears.

Case had at least 2 other fails I know of so 3 total... Scott and I both think it's case related at this point

Add nose cones, that will fix it Tim

Yes!! Haha

Problem is that after Mercury Dropped the TRS line and about 4 years after that, they started to outsource the gear sets to CHINA and the quality of the gears were poor and the specs along with the Rockwell Hardness were not on par with the original Spec'd Merc Gears. So if you have the opportunity to find sets that were sitting on a shelf for 20 years, they are better then the later versions. Just my 2 cents on experience. Sometimes you can find originals, it took me a long time to find a couple sets, I think I got them from Mel Riggs, but that was 10 years ago......the box was dusty then......lol

the ones I had were in very old boxes also, for sure been sitting but no way would I know China or merc they seemed merc to me lol

I'd probably have the case magnaflux texted on the bearing races and/or a liquid penetrant test to see if there's any cracks anywhere...

Or maybe just stop driving like an a$$$hole..lol

Hah!!!