Don't write off that clunk sound. I had a clunk sound and then my mileage reduced a few miles per gallon. I thought the decrease was the new tires I had put on. After another set of tires, it was still low and started getting lower. RPMs started settling around 3k at 65mph. The problem was the torque convertor solenoid. At 68k miles (normally out of warranty but I had purchased the 120k) the transmission finally started reporting it. I was 2k miles away from home at the time. It made it home but only got about 29mpg the whole way. Nissan is replacing my transmission today. The code that finally came up was P0740. I drove with the clunk, then loss of power, worse gas mileage, then surging at take off, for 38k miles before the transmission gave a code so they could find the problem. Still love my Versa but the CVT is not built tough enough for hilly roads. Everyone I know that has a Versa in our area has lost a transmission now.