FONTANA, CALIFORNIA -- I bought a new 2008 Kia Sorreto in 2008. I was impressed with their warranty of 100k or 10 years on the drive tran. I have approximately 61k on the vehicle. I started to hear a roaring noice. I took the car to the dealer and they told me the rear differential was covered under the warranty but I would to need produce proof that differential had been served. I have had my car served their and never was it suggested that I have the rear diferential need servicing. The company and dealer have refused to fix my car under the warranty. I talked to several mechanics and they told me that most cars do not need rear differential service until a 100k. I will never buy another Kia again and I would recommend that no one else does either.