One of my biggest considerations before buying a vehicle that can have a significant factor on me if it goes down is to make sure the motor, tranny and rear end is oil sampled and sent to a lab. I don't do this for my grocery getters, but for my semi or a van where serious breakdowns on the road can cost money even if you are mechanically inclined. I did this for our Chevy express 3500 with 300,000(fleet vehicle) the oil samples came back showing wear levels lower than normal, little research showed motor had been changed. So I got a $800 dollar van with a new motor. Tranny shows wear but is still within limits. I used Blackstone I recommend taking a sample every time you change fluids it will worn you of problems coming before you have a major one on the road.