this is what i got from a 350z forum which has the same 6mt as the g35 do. noise came whenever "a lot" of torque would be applied to the rear end for example starting out in first gear, shifting 2nd to 3rd. but it not such a click it was more like a clack sound, more like metal on metal sound.

as it turns out the rear axle axle needed to be retorqued. this is the exact text from the repair order

16359 DRIVE AXLESHAFT NUT NOT TORQUED WITHIN SPEC W4 STRAIGHT TIME 2.0HRS LISTEN TO NOISE WHILE DRIVING WITH CHASIS EARS, FOUND NOISE COMMING FROM REAR DRIVELINE AREA UNDER ACCELERATION, TIGHTEN ALL BOLTS ON DIFFERENTIAL & REAR SUBFRAME, CKDRIVESHAFT, THIS DID NOT RESOLVE THE INCIDENT, REMOVE REAR HALF SHAFTS & INSPECT, RETORQUED BOTH SHAFTS WHICH RESOLVED INCIDENT, ROAD TEST CAR & NOISE IN NOT THERE ANYMORE

ALSO:

change the trans fluid around 5000 to 10,000 miles as they are metal shaveing in the fluid... this should make the shifting a lot more smooth... well thats all the info that i found for the notchiness and clacking sound hope this helps all of you who has this prob, as i do. and guys its not a shity cluch its just high porformance expect it. GOOD LUCK ALL ; )

 

I've noticed that in my 5AT, I'm hearing the "clunk" while manually shifting from 2nd to 3rd gear and it's more pronounced at higher rpms (more aggressive shifting). Did this solve your issue by the service order done above? Did they charge you for this issue and if so what kind of expense should we expect?

 

Wow, That a good thing to know...