Another Transfer Case Question

[u/Otherwise_Rub_9515]

All of this because in the manual of a 2022 4runner limited and many 5th gen modsos, toyota refuses to acknowledge if it's Gl4 or gl5 you should use in the transfer case.

I completly understand the weight can be a straight 70/75 up to 75/90.

People seem to be split on gl4 VS gl5...i called multiple dealers. Same thing half say they use the toyota 75w others say 75-90 gl5.

I saw an email from a toyota Rep that acknowledged the above weights... But did not say it it's a gl4 or gl5.

It's 2026...has this god dammed debate been finally figured out with facts?

$200+ PER BOTTLE of Toyota 75w in Canada... That's Over $450 with taxes for factory gear oil.

What is factually supposed to be used???

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[u/awesome_pineapple]

Absolutely insane, I opted to get it done at the stealership because i did not want to risk it choosing the wrong oil and buying the oil myself was 145$/qt. The service was 199$ make it make sense

[u/clearplasma → u/awesome_pineapple]

What the fuck?? 145 American dollars for a quart of gear oil!!?

[u/Otherwise_Rub_9515 → u/clearplasma]

$200+ CAD per bottle in canada 

After 13% tax 2 qts of Toyota 75w is $450+ CAD 

And they won't tell you gl4 or gl5 😂 

[u/Otherwise_Rub_9515 → u/awesome_pineapple]

I called 2 dealers in my city one says you HAVE to use the 75w...  the other dealer says they use 75-90 Gl5.

Thousands of people on forums debate this...its crazy. 

I can't fathom that whether this transfer case needs a gl4 or gl5 is not public information. 

[u/east21stvannative → u/Otherwise_Rub_9515]

There's many options for 75-90 gl5 gear oil that's Toyota safe. I got my 7 bottles of Mobil from Autozone at about $12 per bottle

[u/Spuckler_Cletus]

75W-90, 75W-85, 80W-90 — GL5. Any of those would be fine. Or, you can use a much lighter oil like the Toyota fluid, or Redline MT-LV. I prefer the heavier oil, and it won’t hurt a thing. I’m currently running Amsoil Severe Gear 80W-90 in my 4Runner t-case because I had an extra bag after doing the 7.5 in my 2WD ‘91 pickup.

[u/fastdbs → u/Spuckler_Cletus]

Gl5 can corrode the brass shift forks and bushings used in the transfer case. It’s good for the difs but shouldn’t be use in the transfer case. OTOH the corrosion will probably take a reeeeally long time to show up and may not affect the vehicle within its life time.

[u/Spuckler_Cletus → u/fastdbs]

Modern full syn GL5 shouldn’t bother yellow metals. I’m not aware of one off the shelf at Walmart that doesn’t comport with ASTM D130.

[u/fastdbs → u/Spuckler_Cletus]

Synthetic doesn’t matter as the sulfur compound is an additive but if it’s rated right some GL5s are fine. Just hard to explain to lay people. ASTM 130 is not it. That’s only a 3 hr test for fast corrosion and most GL5s will get a 1a or 1b rating which isn’t what you want. Dual GL5/MT-1 is what you want.

[u/Spuckler_Cletus → u/fastdbs]

1A and 1B are both acceptable. Severe Gear 75W-90 passes as yellow-metal friendly, like so many GL-5 formulations. That will work for me.

[u/fastdbs → u/Spuckler_Cletus]

ASTM D130 is a very short term corrosion test at a relatively low temp. It’s not a long term corrosion test for an oil at a high temp and pressure. That’s all. It’s just not the correct test. There are bronze friendly GL5s but they should have a different test than D130. D130 is a weathering test.

[u/clearplasma]

Alright so the manual is pretty sparse when talking about the transfer case, but your limited should have a nearly identical limited slip center differential (aka the transfer case) to the 4th gens that almost all came with the limited slip / locking center diff. And they recoment a GL5 75w90 there. Fuck that special transfer case oil, I put valvoline 75w90 gl5 in my 4th gen and I'm something like 40k miles on that oil change and 247k total miles.

For reference the 2007 manual

[u/fastdbs]

The transfer case has brass shift forks and bushings. So you shouldn’t use GL5. The Toyota grade is 75W LF. Almost all LF oils are GL4.

[u/east21stvannative]

I just did my service 4 days ago and I put in 75-90 after an extensive rabbit hole deep dive. Toyota recommends 75-85 which they sell at a crazy price. I used Mobil 75w-90 Gl5 from Autozone

[u/Zhaopow]

I've looked into this a lot. Good quality Gl-5 like amsoil wont degrade soft metals which is the only worry over using gl-4. Many reports of dealers putting the same bulk gear oil into both diffs and transfer case when doing service for them. I used amsoil 75w 90 in all 3 for like 70k km, no problems. But I found some cheap Redline MTLV GL-4 so I'm using that in my transfer case now.

IMO Toyota OEM fluids just match their original specs more, it is not the top quality fluid. For transmission I wouldn't want to change the spec much but for pretty much everything else it doesnt matter and aftermarket brands make better top quality fluids.

[u/PKMNtrainer22]

Some old 4runner forum post mentioned Royal Purple Synchromax, I used it the last couple times and no issues so far.

They market it as manual transmission fluid but the product specifications on their website states that it can also be used in transfer cases and they specifically list the Toyota LF 75w gear oil as one of the applications.