About 4yrs ago we declared bankruptcy. By law we had to file our trailer that we live in under it. We never re-affirmed the loan, which means we live here because we make the payments and choose to. I think by law we aren't obligated anymore. Anyway, I was wondering, if we decide to walk away from it.. will a repo go on our credit. Or do they not consider a repo as it was filed under bankruptcy? Also, what happens to the taxes we owe?

What taxes? Generally, taxes are nondischargeable. It is probably OK for the lender to report the repo on your credit because it is not an attempt to collect money from you, which is prohibited by a permanent injunction at the conclusion of your case (see your discharge). You should try to either pay the trailer debt off by making payments over time or sell it.