Help with 2019 Tacoma diff oil

@Grizzly123

Another consideration for you:
The Transfer Case takes 1 Liter of oil (1.1 Quarts). The Toyota Oil comes in a 1 Liter can, and it is exactly enough to fill the Transfer Case.
If you use something else, you will need to buy 2 Quarts, because it will take 1.1 Quarts to fill your Transfer Case.

As rarely as this service needs to be performed (once every 5+ years ?), the cost of the Toyota Oil is rather insignificant; and it is definitely the correct stuff.

 

Yep. All right thank you. But if I leave the transfer case and just do my front and rear diffs that would be ok if I decide to do that. I mean I really want to do all 3 so it's done but. I am being told I can use 75w-85 or 90 I mean if you think about it it's way better protection as long ad it's GL-5

 

I use 75 140.

 

From what you have written I don't believe you understand just what the GL-# indicates. Yes, the number indicates a higher performance specification -- however higher isn't always better here, pull up a chair as this will take a minute.

If you are referring to the transfer case, the specification is for a 75 grade Type LF oil, it specifically DOES NOT call out for a GL-4 or 5 performance specification.

GL rated oils, or more correctly the additives in the oil, are exceptionally good at staying in place (protecting) under the twisting loads that are common in an axle. The additives are called Extreme Pressure additives, sulfur is a common one thus the strong sulfur smell gear oils often have.

Take a good look at the ring & pinion gears below, notice the angle of the teeth on the ring gear and also the spiral look of the pinion?
The gears are made that way to give more contact area, it makes the gear stronger (and quieter) than a straight cut gear.
Now visualize how the gear teeth would twist as they meshed and think of the tremendous friction it would create.

Gear oils are compounded to protect against this twisting friction, the additives are designed to stay on the gear, the higher the number the better the protection. For an axle -- so far, so good.




The Toyota transfer case oil is specifically called a "Transfer Gear Oil", the transfer case isn't subject to the twisting friction found in an axle, the high amount of EP additive isn't required (or desired) here therefore a GL-# oil isn't specified.

Here is a very clear example of why specifications are important:
The manual transmission in the Tacoma specifically calls out a GL-4 oil, the reason being that the "better" GL-5 oil is so good at staying on the surfaces it has been discovered that it microscopically rips bits of metal off the brass/bronze synchronizers, causing them to wear out very quickly. This is called "yellow metal erosion", yes - the oil is "so good" it causes damage.



Folks often get so focused on "best" products or brands they forget the object is to have the correct product for the job.

Lets use 3 common oil brands for an example: Mobil, Valvoline & Red Line -- all are high quality products with long histories, readily obtainable and comparably priced. Sounds like you can't make a bad gear oil choice doesn't it?

But in our example you happen to need window wash -- all 3 brands would make a crappy window wash -- not due to quality or performance but because they aren't the correct product to do the job.


Please stop assuming and stop listening to "a lot of people", listen to what the Toyota engineers said and you will be fine.

 

If you're doing Redline, 75W-85 or 75W90 for the diffs and MT-LV for the transfer case.
You're overthinking it.

75W-85 is to eke out CAFE mpg.
75W90 would be an acceptable substitute.
Better protection from one over the other? That's debatable...

The substitutes for Toyota 75W LF transfer gear oil, such as Ravenol MTF-3 and Redline MT-LV, are more like an advanced GL4 low-viscosity manual transmission oil and not like a multi-viscosity GL5 gear oil.

FWIW, my first service was Redline 75W-85 in the diffs and Toyota 75W LF in the transfer case.
My next service will be Redline

$29 75W-90 Synthetic Gear Lube - 1 Quart (Pack of 2)

75W-90 and Toyota 75W LF.

 

Well there's always this stuff for $25 a bottle that will work just fine.

RAVENOL J1C1003 MTF-3 SAE 75W Full Synthetic Gear Oil - 1 Liter for Manual Transmissions, Differentials & Transfer Cases

https://www.amazon.com/Ravenol-J1C1003-Manual-Transmission-Fluid/dp/B00QPCL7ZE?adgrpid=1342504260933083&hvadid=83906755376553&hvbmt=bp&hvdev=c&hvlocphy=101586&hvnetw=o&hvqmt=p&hvtargid=kwd-83906858626978%3Aloc-190&hydadcr=5742_13190780&keywords=toyota+transfer+case+oil+75w&qid=1664768696&qu=eyJxc2MiOiIxLjg5IiwicXNhIjoiMC45NCIsInFzcCI6IjEuMjQifQ%3D%3D&sr=8-3&th=1

 

Nice write up...

I'd like to point out that since you referenced Mobil, there is no Mobil gear oil product suitable for applications requiring GL4 oils. Amsoil, Redline (MT-90 is my favorite), Stalube, Royal Purple, Pennzoil (synchromesh), and several others do...but it's very hard to find on the shelf at most auto parts stores.

 

Thank you.
The OP wanted to put the same oil in the axles and transfer case, he has an automatic.

Agree, GL-4 rated oils for the manual transmission are difficult to find stocked on any local store shelf, NAPA would probably be the best bet.

I used Motorcraft XT-M5-QS in my manual, it meets Toyota specifications and made a nice improvement over the factory fill.

https://www.motorcraft.com/us/en_us...ull-synthetic-manual-transmission-fluids.html

Rock Auto had the best price when I purchased it.
https://www.rockauto.com/en/parts/motorcraft,XTM5QS,transmission+fluid,13630