I was backing up in my driveway which has a small upgrade. I have back up into it many times before but this time I was backing up and at where the incline is the steepest I heard a loud pop or bang. I immediately put the clutch in and rolled it down the hill. I put it in 1st and it worked and I put it in reverse again and it works as well. Did I just pop it out of gear or is it something more serious?