unhappy with 80w-90 gear oil

General discussion about our beloved Tercel 4WD cars
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timothygodden
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Re: unhappy with 80w-90 gear oil

Post by timothygodden » Wed Jun 01, 2016 5:18 pm

Gl5 EP additives are too high (like 6-7%) for brass synchros, fine for more modern synchros made of steel or carbon fiber but hard on the brass. While GL5 will not corrode your synchros (the EP additives act as a protective layer) it will shear off a small amount of brass with this protective layer when the synchro is used. GL4 EP additives are more around 4%, it does not bind as strongly and brass synchros don't lose any material.
People using GL5 in their tercels and never having a problem? If you know how to properly drive a synchromesh transmission (e.g. No speed shifting) your synchros won't need to sacrifice the protective layer and therefore wont lose any brass. Proof that proper operation of equipment is just as important as proper maintenance.

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ARCHINSTL
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Re: unhappy with 80w-90 gear oil

Post by ARCHINSTL » Wed Jun 01, 2016 5:45 pm

timothygodden wrote:People using GL5 in their tercels and never having a problem? If you know how to properly drive a synchromesh transmission (e.g. No speed shifting) your synchros won't need to sacrifice the protective layer and therefore wont lose any brass. Proof that proper operation of equipment is just as important as proper maintenance.
Well, since I've used GL5 80W-90 in both the Terc for 10 years (dunno what was in it before) and my '88 Dodge/Mitsu p'up since new - I guess I'm in the "experienced' category.
But then, I've never owned an AT: Now driving for - AACCKK! :shock: - 60 years this year.
Tom M.
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NWMO
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Re: unhappy with 80w-90 gear oil

Post by NWMO » Wed Jun 01, 2016 9:24 pm

4wdchico wrote:Once again I will state that I believe that Redline 75-90 NS is the best lube for the t4wd trans.

Link: http://www.redlineoil.com/product.aspx?product=58304

Cut and paste from the above link:

Improved copper corrosion protection to prolong synchro life
I considered the Redline products as the tech specs looked quite good. However, Redline indicates in the provided link that their product is NOT for differentials with hypoid gears. With the shared sump, it seems the oil needs to be suitable for the hypoid gears as well. Maybe that line is a CYA for them and it works fine, but it was enough to sway me. Also, the GL-5 carries more weight with me as to NOT being suitable as I believe it relates to the fluid "shear" and "grip" characteristics that contribute to synchro wear based on the article.

All that to say, the differences discussed may all be small enough to not really matter. Clearly many here have and continue to use the GL-5 without apparent issues.

Chris


PS - The Amsoil product I chose closely resembled motor oil (in appearance and flow) vs the "heavy" gear oil removed. I've not noticed any difference yet.
Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
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"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
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The Professor
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Re: unhappy with 80w-90 gear oil

Post by The Professor » Wed Jun 08, 2016 1:53 pm

4wdchico wrote:Once again I will state that I believe that Redline 75-90 NS is the best lube for the t4wd trans.

Link: http://www.redlineoil.com/product.aspx?product=58304

Cut and paste from the above link:

Improved copper corrosion protection to prolong synchro life
Redline themselves suggest a different fluid for the 6-speed Tercel: MT-90 75W-90 GL-4 gear oil

Offers quicker shifts, perfect synchronizer coefficient of friction
Safe for brass synchros, as it lacks the reactive sulfurs found in most GL-5 oils that cause damage
High performance gear protection and longer synchro life
Eliminates notchy shifting, even when cold


I'm about to order some and will check back in to let everyone know how it does. My main problem at this point is a crunchy 3rd gear syncro that was not present before I did a trans oil change.
1975 Subaru SuperStar wagon
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1987 Subaru RX 3-door, x2
1987 Subaru RX Type-RA 3-door
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Mac
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Re: unhappy with 80w-90 gear oil

Post by Mac » Sat Jun 11, 2016 5:13 am

Redline MT-90 would be your best bet as it is designed for a fwd manual transmission requiring gear oil, if in doubt e-mail redline with your questions they usually get back in 2-3 days.

If your lucky enough to still have an owners manual, it says in it to use a gl-4 or 5 oil (i guess gl3 was still available back in the early 80's) i dont think brass has been used in a transmission since the 50's
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timothygodden
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Re: unhappy with 80w-90 gear oil

Post by timothygodden » Sat Jun 11, 2016 9:53 am

Mac wrote:Redline MT-90 would be your best bet as it is designed for a fwd manual transmission requiring gear oil, if in doubt e-mail redline with your questions they usually get back in 2-3 days.

If your lucky enough to still have an owners manual, it says in it to use a gl-4 or 5 oil (i guess gl3 was still available back in the early 80's) i dont think brass has been used in a transmission since the 50's
MT stands for manual transmission not manual transaxle. Redlines mtl, mt 85, and mt90 are not good for hypoid gears, says so right on the bottle and the website, and I broke two teeth off my front pinion using the mt90. Redlines gl4 75w-90 is what you want for our transaxle if you use synthetic I believe it is redlines only gl4 that is recommended for transaxle. Our synchros are most definitely made out of brass, never seen another metal with that color. Yes the fsm states gl4 or gl5 (it also says the 3A should be set at 5* but we all know 10* is best), however the recommendations are most likely out of date and were never properly renewed. Don't blindly trust your fsm even toyota is prone to human error. The original fsm for the 20v blacktop tells you to put your exhaust cam gear on wrong, causing bent valves, and head damage. Unless you have access to Toyota's factory manual archive, which is updated regularly, you should take every recommendation with a grain of salt cause your manual is thirty years old and who knows what knowledge has come to light since then. The SAE technical committee papers is a good place for up to date info on oils.

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Re: unhappy with 80w-90 gear oil

Post by Mac » Sat Jun 11, 2016 12:22 pm

TBH i stopped using redline oil, too many coincidental damages after using but people seemed pretty hell bent on it. Not getting into a pissing match about everything else you wrote.
Tercel 4WD "POWER WAGOON" with 4A-C
aka: "no powa steering tercel, oh oh oh!"
mods: ignition at 10 DBTDC and 90 octane gas.

timothygodden
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Re: unhappy with 80w-90 gear oil

Post by timothygodden » Sat Jun 11, 2016 3:24 pm

I am not the biggest fan of redline either and I feel people should be made aware that only one of their gear oils is safe for our transaxles.

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marlinh
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Re: unhappy with 80w-90 gear oil

Post by marlinh » Thu Sep 14, 2017 10:30 am

I know this is reviving an old post but I am researching which oil to use for cold shifting. Has anyone tried the MT-90 75W90 that Redline suggests?

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Petros
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Re: unhappy with 80w-90 gear oil

Post by Petros » Thu Sep 14, 2017 12:22 pm

I used synthetic MTF and found it was so slippery the syncros did not work, got a gear clash with each shift. It also leaked out all the old seals like crazy.

I changed to a 50/50 mix of synthetic MTF and regular gear oil and it solved both problems.
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The Professor
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Re: unhappy with 80w-90 gear oil

Post by The Professor » Fri Sep 15, 2017 8:11 am

marlinh wrote:
Thu Sep 14, 2017 10:30 am
I know this is reviving an old post but I am researching which oil to use for cold shifting. Has anyone tried the MT-90 75W90 that Redline suggests?
I bought a jug of it, but have yet to dump it into the trans. I will report back once I do.
1975 Subaru SuperStar wagon
1984 Subaru Turbo-Traction wagon & Turbo-Traction hardtop
1987 Subaru RX 3-door, x2
1987 Subaru RX Type-RA 3-door
1987 Toyota Tercel SR5 wagon
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2002 Subaru WRX sedan
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Petros
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Re: unhappy with 80w-90 gear oil

Post by Petros » Fri Sep 15, 2017 12:26 pm

our transmissions, particularly the syncros, were not really designed to work with the low viscosity extra slippery modern synthetic gear oil. Some say they have used it without issue, but i also know several forum members had the leaky seal and gear clash shifting issue, as I did. A 50/50 mix seems to give you a good combination of the extra protection of the synthetic gear oil and the normal operation of seals and syncros. that is what I recommend, it also costs less to make your own synthetic blend than to use all synthetic gear oil.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

The Professor
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Re: unhappy with 80w-90 gear oil

Post by The Professor » Mon Sep 18, 2017 8:17 am

Petros, the problem is that this transmission didn't grind or balk with the old, smelly, black water that was in it when I originally drained the fluid. All I could find at the auto parts store was some weight that was waaay off (I'm sure you can find my post).

This is pretty much the only fluid that meets the criteria for our vehicles. Nobody makes a readily available dino-oil in the right weight while still being a GL-4 rated oil.
1975 Subaru SuperStar wagon
1984 Subaru Turbo-Traction wagon & Turbo-Traction hardtop
1987 Subaru RX 3-door, x2
1987 Subaru RX Type-RA 3-door
1987 Toyota Tercel SR5 wagon
1999 Subaru Forester S
2002 Subaru WRX sedan
2019 Subaru Outback 2.5i Limited

xirdneh
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Re: unhappy with 80w-90 gear oil

Post by xirdneh » Tue Sep 19, 2017 12:11 am

Why gl4? My manual says gl5
Love those Tercell 4x4 wagons but they sure suffer from road noise.

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NWMO
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Re: unhappy with 80w-90 gear oil

Post by NWMO » Tue Sep 19, 2017 7:40 am

Hey marlin,

Sorry for the slow reply, I know that can be frustrating. Here is link to a blast from the past when I was making my decision.

viewtopic.php?f=2&t=12102&p=93219&hilit=gear+oil#p93219

I did choose the Amsoil GL-4 product and have had no issues (only 25k-30k miles though). We get sub zero once in a great while, though not often, but cold shifting was not a problem.

Chris
Psalm 37:4 "Delight yourself in the Lord and he will give you the desires of your heart"

In remembrance of my friend ARCHINSTL:

T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit."
T.S. Eliot - "The Love Song of J. Alfred Prufrock"

"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates."
Mark Twain

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