We Took Our Car To Mexico. Can It Still Be Repossessed?

You have a small window of time to give it back (usually a few months depending on the state) but, Yes, there are repo scouts in mexico hired to find cars and withholding it when your loan is overdue, after this window of time, that is criminal - grand theft auto/fraud, only makes it worse by crossing an international border, now you commit other crimes as well... PS - the gov't has cameras at the border to monitor this sort of traffic and will likely have a record that it left, time/date and all as well so don't think you can play dumb. They will report that to the insurer and lien holder. Best you return it to the lender within your window of time to avoid a serious snafu!