I had this issue with my 2009 370z Base Model.
Rear left axle had the clunk noise.
I took it twice to the dealer and the noise came back.
The dealer service guys were very difficult so, i called Nissan Consumer Affairs.
immediatelly, the dealer became verynhelpful and polite.
they tried one more time to disassemble and lubricate the rear axles and suspension.
the noise went away for 6 weeks and came back.
once again i took it back to them. they then tried to push it to the extended warranty company.
i told them that they would have their claim refused since this was included in the powertrain warranty.
finally they honored the factory warranty and changed my left rear axle.
its been only 2 days, so im keeping my fingers crossed that the issue is gone.
2 thumbs up tu Nissan Consumer Affairs that follow up my case all they way until the end
