Not sure what you're driving, but I just had an entirely new transmission put in my 05 Sentra Spec V last week. Basically wake up, drive out of the garage and the Check Engine light comes on, starts making a strong clicking noise, then it feels like I hit a brick wall. The dealership I went to said that my transmission looked like it had been ground to a pulp. Come to find out it had been bad before I purchased but it took all this time for it to become inoperable. I've heard of a few others having tranny problems on this model so if that's your model, there you go.