GMAC Auto Loans has been rebranded as Ally Financial; contact them by calling 1-888-925-ALLY(2559). Their hours of operation are Monday through Friday 8:00 a.m. to 8:00 p.m., and Saturdays 9:00 a.m. to 4:00 p.m.; they are closed on Sundays.
Ally Financial's website offers a wealth of information regarding their auto loans. Visit http://www.ally.com/auto/ to enroll in auto online services, retrieve account information or make a payment. For scheduled payments, Ally Financial can be reached by mail at PO Box 33115 Knoxville, TN 37930. They can be contacted for payment disputes or customer service correspondence at P. O. Box 380901 .Bloomington, MN 55438.