I recently found a Cobalt Green 1996 300ZXTT 5spd w/ 66,000 for sale @ $16,600. It has new tires and brakes and had the 60k tune up done. I went to see the car in the rain and when I left on the test drive I noticed right off the bat when the car started rolling a slight harshness coming from behind me. Happens at all speeds and can be slightly heard and felt. The guy kept telling it was the new tires with the agressive tread pattern. I say no and kept complaining he then agreed it seemed a bit loud and could be a wheel bearing. What do you guys think? Its a whirring type buzzing sound along with a vibration.

Also when I first pulled out onto the road I took it easy being wet out and 300hp... I shifted into 2nd and eased into it a bit more and I'm guessing what I felt next was the axle hop i've read about. Just alot of bouncing/ hard vibration feel. Would I feel this with traction control turned on and off or what? I'm not sure if this car has it, as I don't know where the controls for it are. Was traction control even an option or standard.

Besides that stuff the car seemed nice. The hatch leaks also, can find where. I figured i'll try to get him down to $14k or so... sound like a fair price or am I asking to low because of the low miles?

 

Sounds like the driveshaft to me. Could be bearings but the vibration says driveshaft to me.
Be aware that 1996 models were OBDII converted. So mods are limited to bolt ons bascially cuz you can't mod the ECU.

 

I recently replaced the driveshaft in my car because of a vibration, but it could only feel it in 5th gear at about 2500 RPM. I never heard anything. I had over 150k miles at the time. If this one has only 66k, I'd tend to lean towards something else. Could be differential bushings. Could be something in the differential; which of course means :bling: . The hard vibration you heard was likely wheel hop. The '96 was slightly detuned from previous years (280 hp vs. 300 hp). If I were you, I'd look for a '95. That vibration and noise would've scared me away from buying that one.

 

I'm going to go look at it today when its dry out... also they said they had it looked at and it is a wheel bearing in the rear... dunno though, i'll see later.