80W90 in transfer case and GL5 75W90 in rear diff, or use GL5 75W90 in both?

[KGMtech]

My hyper maintained 2019 QX60 will need the transfer case and rear differential fluid changed in 3k kilometers, I currently have 80W90 in the transfer case and a semi-synthetic GL5 75W90 in the rear differential. Can I standardize these 2 oils with just using the GL5 75W90 for both the transfer case and rear diff?

I do this service every 35k kilometres - which works out to 2 years. The transfer case only holds 300ml and the rear diff about 500ml, so having 1 bottle of each different oil is sort of annoying.

Would you do it?

 

[Kira]

I'd start by conquering any annoyance caused by two small bottles over one (ha-ha).
Seriously, while the two fluids may be very close in character, I'd verify what was called for by the manufacturer and learn if there are any caveats, such as ,"no synthetics in the rear diff".

 

[slacktide_bitog]

I'd do it

You can use 75w90 in both with no problem

 

[V70tdi]

If your transfercase has brass, bronze bushings or other yellow metal parts in it and calls for a GL4 i would not use a GL5 oil when it can be bad for yellow metal parts. So take a look in the manual what type of oil the transfercase calls for. Some oils are specified to GL4/5 that should be ok to use.
I hope you use the word yellow metal for brass, bronze and other yellow coloured metal alloy. I just translate the word from Swedish if not i hope you get what i try to say

 

[TacoTanium]

Hi OP, (@KGMtech), I also have a QX60 and want to do the same as you using 75W90 gear in both front transfer and rear diff.
What did you end up doing?

 

[tvaughn]

Apparently, this is what Infiniti says:

"The manual calls for GL-5 80W-90 conventional (non-synthetic) oil for the transfer case and Semi-synthetic API GL-5, Viscosity SAE 75W-90 for the differential."

I'm unsure of their reasoning, but I personally wouldn't deviate.

 

[KGMtech]

Hi OP, (@KGMtech), I also have a QX60 and want to do the same as you using 75W90 gear in both front transfer and rear diff.
What did you end up doing?

I did commonize the fluids, same 75W90 in both. I don't see any difference from the driver's seat. (Butt Dyno)

 

[TacoTanium]

I did commonize the fluids, same 75W90 in both. I don't see any difference from the driver's seat. (Butt Dyno)

Thanks! I'll be doing to same in both mine and wife's.

 

[JTK]

When I owned my 2019 Pathfinder, I used 75w90 in both. I did the first transfer case drain/fill around 30K miles and the tiny bit of gear oil that drained out was black and glittery. The rear diff fluid never looked bad. The T-case oil takes a serious beating in this drivetrain and is a ~$3K component just for the part, so it is wise to change that little bit of gear oil often given these things are churning any time the wheels are rolling. I did have a local shop do the final drain/fill on the T-case and he used 80w90.

I did 3 T-case drain/fills on my 2019 between ~30 and 75K miles. Did oil/filter changes on that VQ35DD every 3000-3500 miles, yet the timing chains still began their death rattle at ~103K miles, prompting me to part ways with that vehicle. I hope whomever tears into that 35DD finds it spotless. LOL