There is really not much to check unless you were to weigh it and compare to stock.101795 miles. We bought it used with 84000 miles so don't know if the previous owner had changed the filter for sure. I didn't think to ask him about it when I asked how the truck had been used. He did have all the recalls done. When it warms up some I will pull the cover and check the filter. It's 29 degrees and supposed to snow.