I was driving my 1987 bronco with an AOD home from work last night and there was a red light that is usually a flashing yellow and I braked hard. Not the first time I braked hard though. That is where I think it started but I am not for sure. I am pretty sure the odometer is moving at the same speed though which is weird. Could it be a broken speedometer, if I saw you can just replace the speedometer.