An alarming number of Americans with auto loans are struggling to make monthly payments. Auto loan performance saw further deterioration in December, and loan delinquencies jumped. Of all loans, severely delinquent ones have reached the highest rate since the financial crisis about 15 years ago. Recall last month. We pointed out the auto sector finds itself at a critical inflection point as a crushing auto loan crisis nears. The note was titled "Perfect Storm Arrives: "Massive Wave" Of Car Repossessions And Loan Defaults To…