I just bought a 2011 Jeep Wrangler Unlimited with the 3.8L 4spd Auto. It has 160k miles on it and a very small rear main leak. Jeep runs smooth. I have non the service records. I believe I'm the 3rd owner of it. the 2nd owner only had it a 1yr and put 1000k miles on it. He changed the oil and...