I picked up a 2013 g37xs a couple of weeks ago and I've been changing the fluids on it. Already did the atf and rear differential but while looking at how much I need for the front diff and transfer case I noticed on amsoils page it says "synthetic required" for the differential. I used valvoline 80w-90 because that was available at walmart. Do I need to use synthetic? I don't think the valvoline is. Thanks for the replies.

https://www.valvoline.com/our-produc...mance-gear-oil


Bonus pics of car..
https://imgur.com/a/0mUNpeU

 

While I'm not 100% sure, I'm going to say that as long as it's GL5 compliant you should be fine.

Good Looking G BTW

 

If you have the owner's manual, I do believe it lists the requirement on the fluids page(s).

 

I had my 12x sedan serviced at a Pacific Northwest Infiniti dealer a few months back hey used Mobil 1 gear lubes in the diffs and matic J in the transfer case (legit matic J, not S) fwiw. Not sure if synthetic is required or it was just been to pad their profits. . The car does feel quicker now, it has less rolling resistance when cruising and not under throttle, and better low rpm acceleration. The trans was also serviced at the same time, full fluid exchange with Valvoline Maxlife and 2500 miles later all seems well.