The end of last January I had to take my car in because it got "stuck" in 4 wheel drive. I was able to get it out, but it would not go back in. They kept it for two days trying to find a problem and found nothing. They reset something (I left last year's paperwork with them & can't recall what they reset.) It worked fine for the rest of last winter & for the little bit of winter weather we have had so far this year until Thursday morning. So that Chevy is spending a couple nights with our mechanic.