42RH in 68 Dart advice/request

I don't have the Transbrake version. Maybe I should have gotten that one, but I didn't think I wanted to hold a button while backing in/out of parking spaces with manual steering.
I think it was a botched rebuild job. I found a snap ring that everybody says doesn't belong in any Mopar transmission. There is visual evidence of a piston seal that had flipped in part of it's bore ( but I'm not sure if that short a distance would have left the visual "staining") but about 1.5" of it was definitely rolled the wrong way at some point. If nothing else, it was not a "do all the performance tricks" build I had requested. It was a V-6 level freshen up.