Oil Weights for diffs/tcase?

Are you all running

$28 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 in everything? I think the rear/front calls for like 75W-85 or something? Seems kind of obscure to me I don't even think my local parts store sells it. Tcase is 75W-90 if I'm not mistaken which is pretty standard. GL-5 rated for everything? Got a 2018 SR5 which shouldn't need the limited slip additives yeah?

 

$28 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 is just fine, and the 3rd gens do not require a LSD additive.

I do think the transfer case does require the "special" low viscosity lube. However, I've read some dealers just throw 75W-90 in everything. Not sure how that eventually turns out. There is however several alternatives for the uber expensive Toyota transfer case oil.

 

TC wants 75W. Ravenol for the win.

 

75w90 in both diffs. Redline mt-lv will go into the TC when it's time.

 

The transfer case calls for GL-4 Oil

 

Oh really did not expect this?

 

This is the almost way

The third gen wants 75w85 in the diffs and 75w gl4 for the TC (at least for a 4wd Off-Road auto, I haven't looked into the other trims to see if anything is different).

Some have had luck running 75w90 in everything, but any time I change from what's recommended for this stuff I notice notchiness and reduced smoothness or new noises it didn't have before. I changed my fluids at 16k and I swear my truck felt like it was coasting better with Redline 75w85 in the diffs and their MT-LV in the TC makes it engage noticeably smoother and faster (from ~4 seconds to engage 4wd to under 2 and its now silent and doesn't feel like it's straining the truck anymore when engaged).

 

Is it the "correct" thing to do? No.
Is it what I do? Yes.

I've ran

$28 75w-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75w-90 Mobil 1 in all 3 for all my trucks life. Just passed 150k miles, about 120k-ish of those running 75w-90. But again, its not the "correct" spec.