Quick t-case fluid confusion

[amalik]

Hey guys,

The owners manual calls for 75W-90 GL-5 gear oil in the T-case. Simple enough right?

Well, with the weather below 0F (And in Colorado, that happens some months) -- the manual calls for 80W-90 in the Front and Rear differentials.

So is it suddenly OK to have 75W-90 in the transfer case with 0 below or should/can the 80W-90 go in there as well? I would think if it's weather related, 80W-90 would be recommended for the transfer case as well.

Thanks for clarifying.

 

[Grenvilleter]

I would think the 75w-90 is for colder temps. When it warms up it should be the same viscosity as 80w-90 which would be for more moderate temps.

 

[amalik]

The manual does say ' except add' when it recommends 80w... we have automatic differential disconnection from my understanding, so maybe im misreading it and it should be 75w in all 3...

 

[pluton]

Toyota likes 90 or 80W-90 for diffs, except ADD diffs in which they want 75W-90.
Toyota likes 75W-90 for trans and TFR; in reality almost any oil, including motor oil, could go in the TFR.
Diffs need GL-5, no exceptions.
Toyota says GL-4 or GL-5 for the Trans, the community says use GL-4.
In the USA marketplace, 90 or 80W-90 generally means conventional dino-type oil, and 75W-90 generally means syn.

 

[amalik]

Do you know if the 3rd gen is add?

 

[nor_cal51501]

Do you know if the 3rd gen is add?

Yes, the 3rd gens are ADD.

 

[slapdappy]

I put Mobil 1 75-90 in all three after drain, refill, drive, drain, refill. Everything I read and everyone I spoke to said 'meh, no difference,' so I used the same to keep it simple. But don't follow my example because I ignorant.
I think Pluton's correct about the synth 75-90 vs dino weight 80-90 designation because I recall being told the same thing, which may be another reason I decided mobil 1 synth 75-90 is fine across the board.