mike Mroz

I recently purchased an 97 Maxima and have some questions. I'd appreciate any input. When brakes are applied the rt. front makes a rotating cracking, crunching noise. calipers just replaced, pads fairly new and rotors not old. Secondly, The front end sounds loose when going over minor bumps. Ball joints and tie rods check out OK. Third, On the dash the Sensor light stays on, book refers to Exhaust gas Sensor. Do I need to further test or just replace the sensor ? Lastly, Transmission shifts hard and late out of third. Is this a characteristic trait or a problem. I have read other concerns about the same. The car is in excellent condition otherwise, rides, runs great. Was A one owner and has only 67000 miles. Want to get it in A1 condition.