Nissan / Infiniti vehicles do no like anything synthetic. Especially oil. Synthetics are too thin and can cause oil consumption in our cars.

Synthetics are overrated. Why pay more? Does it make your car last longer? No...

Just switch back to the Nissan crap and see what happens.

 

What makes synthetic thin? If you buy the proper spec, the viscosity will be the same. Synthetic or not.

Some OE Fluids have stuff, Aftermarket fluid tries to copy, thats were the aftermarket fluid fails.

Synthetics can handle heat better, which might be beneficial

 

from my own experience i would not put the synthetic tranny or rear diff fluids stick with oem. but to each is own,
i just know it solved my issue as soon as i switched back, only thing synthetic that's going in my car now is engine oil,

 

not sure I would agree with the motor oil part. I think I have had much better experience running synthetic (and now amsoil) motor oil. in fact I would say if I did have a little oil consumption that the amsoil has improved that as it doesn't look like I am loosing much if any... *knock on wood* however it is hard to tell at times.

 

You didn't happen to change one fluid at a time so as to diagnose the cause of the whirring? To me it sounds like my whirring is from the diff but as with many car sounds, the apparent source of sound may not be the actual as the sound travels strangely in a car.