hey there all, first post so please excuse any ignoranceso about 2 months ago i wore a hole in my exhuast and had to take my G35 coupe out of daily rotation, took me about a month to sort it out. got it back on the ground and my new exhuast sounds fine, but my rear end was making basically the same sound as in the video below. took the car down again and dropped the differential as it was leaking pretty bad anyways and needed a reseal at the least, turns out the main gear and pinion had significant wear. magnet was super clogged up, but there was still about 1.5/2 liters of clean fluid.

so whatever my diff went bad

bought a new one

this is my first official test drive with it but its a vlsd out of a 2003 350z making the same damn noise

though this time i was sure i had a visibly bad one (my original), and a visibly good one (new one), and was sure i was putting a good differential in the car

so whats going on here? did i get another bad differential? could something else be making this howling sound? (tires, hubs, brakes?)

also, i adjusted the clutch pedal slack on the pedal itself during the time it was down finding another exhuast. could that be blowing out my diffs?

 

here is the clip needed for context. thanks in advance

 

You can unbolt the CV axle hubs from the differential, on both sides, let them hang, then turn off the VDC, start the engine and run through gears and see if the sound persists.

The ABS/VDC system will be going haywire due to detected wheel speed on the rear but not the front, and no ABS on the rear, might have to unplug the ABS relay as well I'm not totally sure.

I suspect your sound is a wheel bearing though, running without axles attached will confirm that the diff is not the problem. The diff will have a slight whine under normal conditions, the wheel bearings make a faint humming sound when they start to go out, you sound almost like metal on metal a sort of "swishing" sound that's more likely a wheel bearing, or brake caliper sticking, or something like that.

Also about your existing differential, it's common for there to be fairly significant metal buildup in a differential if the fluid has 100k or so miles on it. That's why the maintenance interval is like 30k for differentials, regardless of make/manufacturer, basically every vehicle is 30k for diff or somewhere near that for performance applications, non-performance is usually 50k. One of the main reasons for the shorter maintenance interval is to get that metal out so it isn't killing the thrust washer, not necessarily just because of fluid breakdown even though it's the other half of the reason for that maintenance interval.

 

thanks so much for the helpful information turns out one of the hubs was bad after all, gonna test drive it tomorrow and see if we solved my issue

 

new hub no more wine thanks bro!

 

Glad you got it all sorted out.