Thoughts on using 75W90 Gear Oil GL5 for transfer case vs. recommended LF45W GL5 gear oil

Long ago I decided to perform my own maintenance to my 2016 4Runner SR5 Premium and now I am about to change the oil in the front/rear differential and the transfer case. I have seen many videos on the topic of using 75W90 Gear Oil (GL5) instead of the recommended LF75W GL5 Gear Oil. The only drawback that I have seen so far is maybe a slight (very slight) reduction is gas mileage efficiency.

Any thoughts and what do you use?

Thanks!

Robert

 

Any off the shelf gear oil of the correct viscosity or within the range will work just fine.

 

@McSpazatron might have an opinion on this. He had a transfer case issue and there was some discussion about the gear oil being a contributing factor.

You can read his thread here.

 

Car care nut says it’s ok to use 75w90 gl5, and there’s even a email from a forum member that asked toyota directly about it, and they also said it was fine.

However, I think that’s surprising because aftermarket gl5 gear oils are supposedly not safe for the soft yellow metals that synchros are made of, and our transfer case has one synchro.

I decided to use a a “synchro-safe” 75w90 gear oil at around 35k miles. At 50k miles, my transfer case blew chunks. I lost “shift-on the fly” capability. I drained the oil and a synchro retaining key and synchro sparkles came out. I have not split the case yet to see why it happened, so I can’t say more than something related to the synchro ring failed.

What is the lesson here? I have no idea.

But for people that seriously analyze their options, there is one thing that Toyota 75w LF provides that others can’t. The ability to not have to analyze options anymore.

 

I used Redline MTL

 

If you don't want to use Toyota's liquid gold, I personally think Redline MT-LV is the safest aftermarket choice.

It's a 70/75w GL4.

 

Here's another interesting tidbit I stumbled on that might relate to your case:
"The real shocker of this AMSOIL survey (merely a marketing scheme) is the Royal Purple product that rates 4a. Shocking really for a product that claims it is "yellow metal friendly." 4a is 3rd from the worst possible. "

This shows up a few comments down in this thread:
https://bobistheoilguy.com/forums/threads/copper-strip-tarnish-test-10-gear-trans-fluids.171491/

 

And here are the detailed test results. Super interesting stuff! Really great to have this level of factual information.

https://shop-banks.s3.amazonaws.com/products_data/diff_covers/gear-oil-comparison.pdf

 

What the hell?!? That’s not good! At what point are they lying about the product if it does worse than a regular oil? I wonder if it’s some ingredient in the grape flavoring that makes it more corrosive.

 

Is your T-case stick-shift or electronically actuated? If electronic, go with a low-viscosity fluid like Red Line MT-LV.

This is coming from 3rd gen Tacoma experience where people report 4WD shifting problems with regular 75W90 in the winter.

I wouldn't worry about the GL4/GL5 "yellow metals" business. Millions of 1st & 2nd gen Tacomas and 4th gen 4Runners are spec'd with GL5 oil for the T-case in the owner's manual.

 

Get the proper viscosity, brand doesn't matter

 

Works for me.

 

Cakes are made out of flour, butter, sugar, and eggs. They’re all the same. The baker doesn’t matter.

 

I prefer this brand of fluids. https://oclocalhoney.com/

 

I prefer Capri Sun. Comes in similar pouches for easy filling, and isn't made from fossil fuels.

 

Ohhhh, I see what you did!

 

I’ve been called obtuse before. I tend to blur the line between subtle and hard to understand, especially when I’m trying to stifle the urge to make ad hominem remarks.

 

Truth is more digestible when the delivery involves discovery.

 

Crap, another thread on wildflower vs buckwheat honey.

But yeah, you can stretch intervals on buckwheat. It’s got more undigested pollen bits in it.

 

I go with the synthetic. Actual bee vomit is gross.

https://www.fastcompany.com/90565797/this-honey-is-real-but-it-wasnt-made-by-bees

 

I just used Royal Purple in my diffs and T-case for the first-ever fluid change at 65K. I guess it will explode soon according to ECGS.

 

Gents, I have seen the YT Car care nut video. One opinion. I own a Tundra and a 4R. Both call out the GL4 / 75 W toyota fluid. Crazy expensive. So I researched the oil specification. It is 08885-00705 from Toyota manual. What this crosses to is a fluid from Ravenol that is a 75W 80 GL4. Check Amazon, like $26 a quart, and looking at detail spec sheet meets requirements for 08885-00705 Toyota 75W GL4. I have run this in Tundra for 20K miles with no issues. I feel this is a cost effect solution meeting the spec. Was an electrical eng for 40 years so specs are my go to. Luke
RAVENOL J1C1002 SAE 75W-80 Manual Transmission Fluid - MTF-2 Full Synthetic API GL-4 (1 Liter).
Brand: RAVENOL

 

This is correct.

 

Used it for 35 years and 100s of thousands of miles never issue. Your looking to far into the book

 

Which oil are you saying you used without a problem?

 

Mobil 1 motor oil, 75W90 gear oil and a filter once. It does it all and no fail

 

Do it every 100k with Mobil 75W90 gear oil. Good for 500k but only if happen to forget. I think you're to hung up on the numbers. If that makes you comfy I understand, but your worrying about nothing. Used it 35+ years without fail, blown seal or any failure.

 

Well 97 had bad seals at 265k but they corrected them in 99 or 2000 I believe with a new seal like the ball joints. Still have a couple

 

You do you and I will go with what my experience has taught me. Probably should change it every 2000 miles to be safe