Best transmission oil

What would be the best transmission oil and differential oil for my 2017 Tacoma trd off-road?

 

My bad(sorry) If it's true about GL4 only? then I'll change my picks to this.

$91 Red Line 50305 MT-90 75W-90 GL-4 Manual Transmission and Transaxle Lubricant (MTL) - 1 Gallon

https://www.amazon.com/Red-Line-50305-MT-90-75W90/dp/B002INX20C/ref=psdc_15719351_t2_B000CPCBF0


For Auto, https://www.rockauto.com/en/moreinfo.php?pk=7668692&cc=3441741&jsn=377

This WS fluid is the same as Toyota, but cost less. I've used it for about 12 years.

 

Thank you sir

 

I was thinking the SynPower was not yellow metal safe and was I only recommend for non-synchronized transmissions. I could be wrong

 

I'm a huge fan of synthetic boutique oils, but Toyota AT fluid is fairly cheap and so is walmart Super Tech 75W90, both of which will perform as good as anything else with regular scheduled OCIs.

 

Lubricant specifications (and lots of other interesting things) can be found in section 9.1 of your owners manual.

Differentials and manual transmission can use any brand that meets Toyota specifications
Differentials: 75W-85 GL-5 gear oil
Manual transmission:

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

75W-90 GL-4 gear oil -- GL-4 only -- this is important, no product labeled GL-4/GL-5 is correct

Automatic transmission and transfer case is best to use the Genuine Toyota fluids (in my opinion)
Automatic transmission: Toyota Genuine ATF WS
Transfer case: Toyota Genuine Transfer Gear oil LF SAE 75W

 

That's what I was eluding too in my post. Many, if not all, synthetic GL-4/5 gear oils are not yellow metal safe. They're great in diffs....but will eventually chew up synchronizers and brass materials.

Something like an MT90 is a much safer bet and is a true GL-4 fluid

 

You are going to get a lot of opinions . Its a free country . Enjoy the replies


For the slushbox . A fully synthetic fluid developed in 2019 with LXE technology and completely compatible with the dreaded World Standard semi synthetic fluid https://www.lubegard.com/products/atf/

For the clutchbox https://www.lubegard.com/products/gfs/

 

OEM

 

I used the Motorcraft

$34 XT-M5-QS Full Synthetic Manual Transmission Fluid - 1 Quart, Black

XT-M5-QS in mine, it is also a true GL-4.

 

Any reason Max Gear can't be used in the cog swapper?
https://www.royalpurple.com/product/max_gear/

Claims to be 'warranty compliant'. Specifies not corosive to ferrous and non-ferrous.

I use it in my pumpkins and TC. Last taco was an auto.

 

Two quotes from the product data sheet:

"Max-Gear meets or exceeds OEM warranty requirements for GL-5 automotive rear axle hypoid gear lubrication."
I would say that this would imply a warranty if used in an axle application.

"Max-Gear also is safe for GL-4 applications or bronze synchro gears"
Here they carefully did not say "meets warranty requirements" -- they said it was "safe".

There are true GL-4 products readily available that meet Toyota specifications and are proven to do the job. What would be the benefit of moving outside of these products?

Not liking or disliking RP products.

 

Amsoil gear oil in rear and front diff. Being that's in a squeeze pouch makes easy too , Toyota OEM in Transmission and transfer case. Engine oil I like Mobil 1 Extended Service, ofcourse synthetic 0w20

 

1 Oil to lube them all.

I had RP in my carriers for 80,000 at one point. Looked almost unused when drained...only the purple color had faded a bit. I'm sold that it is indeed quality product and have no reason to doubt it. Toyota oils are surely of good quality, but they are only made to a spec, and that spec is not completely decided by performance...costs are factored as well. By tapping the aftermarket, you can get oils that meet the specs and sometimes exceed them offering additional benefits. The question is whether the actual benefits are realized vs cost over OEM. Plenty of tires out there that are DOT approved.

I won't be changing it for years, but doing my dilligence right now.

 

Genius is sometimes found in 'mundane' things.

 

Just from my experience from having a tundra, the differential oil ins't a big deal, all the synthetics of the viscosity recommended work fine....i preferred amsoil. The automatic transmission was another matter. I was always recommended to use toyotas atf.

 

@RCBS

"1 Oil to lube them all. "
I agree, that is convenient if possible. Why didn't Toyota do that for themselves?

"... I'm sold that it is indeed quality product and have no reason to doubt it..."
I agree, no problem with the RP reputation.

"...Toyota oils are surely of good quality, but they are only made to a spec, and that spec is not completely decided by performance..."

For differentials and the manual transmission I didn't advocate Toyota brand oil, only one that meet the Toyota published specifications.
The product used in the differential is not an issue here, differentials haven't changes much since 1970, any quality 75W-90 GL-5 oil, changed occasionally, should give good service.

The interesting point of the conversation is the manual transmission - Toyota went out of their way to specify a GL-4 oil. GL-4 is an engineering specification, the transmission was designed around this specification. The Royal Purple product doesn't appear to solidly meet this specification, it is not a reflection of the quality of the product, it just wasn't designed for this particular application.

Again, if GL-5 was acceptable why didn't Toyota use it themselves?

Here is good read on the topic if you have an interest.
https://www.widman.biz/uploads/Transaxle_oil.pdf

 

My question is if GL-5 doesn't supersede GL-4, then why not use another spec #? As we know, *typical ascent of spec numbers shows that with each step forwards, the older spec becomes redundant within the new spec. Standardization was meant to end this type of thing and I believe for many years it was mostly succesful, but we are again finding ourselves with a myriad of quite specific specifications from manufacturers that are sometimes contradictory to what some oil refiners list their products as.

I'm still trying to figure out why there are differing anti freeze specs. It's coolant. It needs to: 1, not boil. 2, not freeze. Seems like something simple that some engineers decided to fook up.

Alas, my plan to buy one large container of maintenance fluid is in ruins.

'Again, if GL-5 was acceptable why didn't Toyota use it themselves?' Further, why didn't they design a tranny that could use ATF >>>WS?

 

3. Not corrode the differing designs

It's all about the silicates, phosphates and borates.

 

@RCBS
Toyota didn't use GL-5 because it isn't suitable for the application.
Really we are fortunate that the manual is offered at all. It uses GL-4 gear oil (instead of ATF) because it is a robust older design which was designed around this specification, I consider the older design a good thing.

GL-5 may supersede a GL-4 requirement in a differential application, just not in a transmission application. Design specifications don't become redundant because a newer product is introduced.
Lots of folks get so caught up in selecting the "best" oil when what is really important is selecting the correct oil for the job.

What happened with antifreeze: Fuel economy and emission requirements really.
In 1970 most engines were made of tough cast iron and used what we now call "conventional green" antifreeze. As lighter metals such as aluminum became more common in engines the older style antifreeze couldn't protect the newer metals. Additionally modern engines produce more heat and needed more efficient cooling systems to keep up.

Really the engineers have done a pretty good job over the years all thing considered. You may not be old enough to have lived with cars with breaker points and carburetors, they were easy to fix but required a lot more service than our moderns that may go 100,000 miles on the plugs and start reliably at 20 below zero.

No you can't have 1 product fits all -- but you do get the experience of driving probably what is the last of the manuals, and a really nice shifting one at that.

Extra credit:
If you want to go down a lubricant rabbit hole start reading about the reduction of zinc and phosphor used in engine oils and the effect on older engines designed around these additives.