Ram tranny problems

Well I was playing around changing the tranny fluid and its nothing but metal shavings. Replace with junkyard one or rebuild? I don't want to do it twice and I'm definitely not paying some of these tranny places 2 grand. I have all the tools to do it but I've only done one other tranny and it was out of a jimmy. I think a 4L60E? Maybe? Its been a while like 7 years ago. Same concept on basically all rwd trannys right? I just don't want to get over my head but I don't want to pull it back out if the junkyard one belongs in the scrap pile too. Opinions?