If the previous owner welded the diff....replace it.

 

^^^

If that's the sound you're hearing, then the diff is either toast (wrecked bearings, etc) or the diff was welded. You got options, you can pick up a used OEM open diff from a base model for super cheap, or you can try to find a used OEM LSD (vLSD) for a bit more cash, or you can go straight for a Quaife or O.S. Giken LSD and get your existing diff pumpkin rebuilt. While you're at it you can get those OEM diff. bushings replaced because they are most likely toast anyway. A new diff is expensive, but sooner or later it would need to get done anyway. If you plan to keep the car long term, it's a worthwhile investment.
-Icer

 

Awesome, i do plan on keeping the car longterm so i will look into replacing it soon. However, I havent identified 100% which trim i have. I believe i have the Track edition or Grand Touring bc i have brembos, matching seat color with brembos and navigation. Its an 03, 6mt, steering wheel has no controls. With that being said, i believe i have an LSD in mine so i would have to find a replacement LSD. Thanks to everyones help in this thread.

 

http://www.slidegood.com/nissan/350z...ntial-assembly

and then drop yours, slam quaife in it, swap out again and sell this one

 

There's plenty of VIN decoder websites which will tell you all the trim information you need for free. Just copy and paste and let the database do the work.
-Icer

 

Bring this thread up again bc i wanted to see if any of you know if its uncommon for there to be a rattle that could be due to differential? I was in a drive thru line angled and there was a rattling sound coming from rear. Then when i straightened out, it went away. Skipping only happens when turning.
Does the diff have mounts or what could be causing that rattling noise? And lastly, could changing the diff fluid temporarily fix the problem or atleast not be as bad? ALSO, should i bother getting quality diff fluid with the off chance i would probably just have to replace the diff? I dont want to spend more money than i have to

 

My guess is diff was welded and then the welds broke

 

^^ What trav said.

I wouldn't even spend the money nor waste good quality diff fluid on a suspect "grenade-ed" diff. Even if you have a failed diff bushing (leaking black ooze down rear subframe), I haven't heard any reports of people noticing a loud rattle under these conditions. Now note, that you will hear an audible rattle coming from the clutch throw-out (thrust) bearing while sitting idle in neutral. This is perfectly normal and all 6MT Z33s exhibit this behavior. It's usually pretty easy to pinpoint this noise as coming from the bell housing with the window down, engine idling, and pumping the clutch pedal while in neutral. Just thought I would point this out to avoid confusing a "normal" noise from an "abnormal" one.
Good Luck!
-Icer