unhappy with 80w-90 gear oil

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irowiki
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Re: unhappy with 80w-90 gear oil

Post by irowiki »

Drain it again, fill with 50/50 mix of atf and gear lube. Get it hot by driving for a while at highway speeds, but be easy on it. After about 50 miles, drain it out and put good gear lube back in.
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Re: unhappy with 80w-90 gear oil

Post by The Professor »

irowiki wrote:Drain it again, fill with 5050 mix of atf and gear lube.
And run it with the ATF for the length of the trans oil change interval? Have you been running this cocktail and for how long?
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Petros
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Re: unhappy with 80w-90 gear oil

Post by Petros »

not recommended to run the ATF mix very long (ATF is only about 5 wt oil). A few days at most, go easy on the trans, but get it up to speed a few times so it warms up good to help break down the glaze build up. ATF is a very strong penetrant and detergent action and sometimes can work wonders to clean out and get a tired manual trans working well. It does not always help, but it does work often enough that it is worth a try, and far cheaper and easier than any other trans repair you might try.
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irowiki
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Re: unhappy with 80w-90 gear oil

Post by irowiki »

It must have submitted before I was done with my post (was on mobile). I fixed the post.
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jimcrazy
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Re: unhappy with 80w-90 gear oil

Post by jimcrazy »

i changed over to this lucas 80-90 gear oil. its about as thick as 40 weight oil flows well even in the cold
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Re: unhappy with 80w-90 gear oil

Post by Mac »

Redline mt-90. Ftw.

Remember to fill from the rear most fill plug.
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Re: unhappy with 80w-90 gear oil

Post by kamiphloj »

Something to know about gear oil.Not all gear oil is good for transmissions.GL 4 is good for transmissions.GL 5 may not be.It has been a while since I did the research,memory is fuzzy.
It has to do with yellow metals.Bronze,Brass,etc.Like synchros.The EP additives in GL5 rated oils are good for the loads on hypoid gears.Use it in your axle.
But trans gears do not have those loads.The GL 5 additives attack yellow metals.Use GL4 in your tranny.
If you go to Mobil One's web page,you can find a recommendation against using Mobil One gear oil in manual transmissions.
As I recall,Royal Purple was OK,but do fresh research.
Stay-Lube makes a GL-4 available at NAPA.

Long ago I had a52 Ford pickup with a crash box trannie.No synchros.Thereis a feel,a rhythm,a sense of shifting.I DO NOT suggest you practice with your Tercel,but driving that old Ford taught me how to shift up or down without clutch or synchros.

As you upshift to a gear with a weak synchro,feel the synchro just as you are engaging.If you crunch,you went too fast.Allow the engine RPM to drop to the correct RPM for the gear.There is a sweet spot where it will fall in to gear with NO synchro.

Its a skill you can learn.
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Re: unhappy with 80w-90 gear oil

Post by dlb »

the FSM specifies GL4 or 5 for both the trans and diff.
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Re: unhappy with 80w-90 gear oil

Post by Mad_Marx »

I drained and refilled the trans and diff on my 86 at 215,000. It was having problems with the 1 to 2 shift. I used Redline full synthetic 75-90, it was like having new syncros installed, I've been very happy with it. We get down to sub zero temps here a few times a year, and although it feels a little stiff it still shifts fine.
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Re: unhappy with 80w-90 gear oil

Post by kamiphloj »

I do not represent myself as an expert.I've been gone from the forum for several years.I have an 85 Toy 4x4 pickup.(and a Terc!)Tending to the gearboxes,and not satisfied with the "expertise" of folks at Autozone,etc,I did enough research on this topic to understand the basic differences between GL-4,and GL-5.I've read some basic API designations,also.
First,there IS a lot of discussion,and vaying opinion,on the topic.Its probably inaccurate to say that ALL GL-5 gear oil is potentially harmful to yellow metals.However,IMO,that is the safe starting point.It is certainly possible that some GL-5 oil is formulated to be OK in synchro manual transmissions.
However,that is not the starting point.Its NOT a good plan to say"I don't know what the designations mean,but 5 is bigger than 4 so it must be better"
I'm out of my league here,but part of the additive ackage for GL-5 oils is typically about phosphorous and sulphur compunds.They work great for EP purposes,and for hypoid type gears,they are the way to go.
Those are not so good for yellow metals and aluminum.
I do not say"Take my word for it"
I say search" GL4 versus GL5 gear oil in synchro transmissions" and come to your own conclusions.
This is one place to start:
http://www.bobistheoilguy.com/forums/ub ... er=1157073

I don't know too much about the synthetic gear oils.I do recall years back an enthusiastic Terc Warrior here handle Typrus suggested dinosaur oil as theway to go in a Terc.Seems like it has worked in my Terc for 32 years.....but,there may be something better.

I do not deny the experience of the folks in temp zones like North Carolina.I suspect something else may be going on.I live in Northern Colorado.
When things get colder than about minus10 f,vehicle problems do crop up,but my 83 Terc has never been stopped or slowed by thick gear oil,down to minus 15 or so.I use dinosaur oil in my gearcases.
I have seen the torn shifter boot/water contamination/frozen shifter problem.

I'd try something more modern,maybe Royal Purple,if the advantages are there.But that may take more testimony than "Cool label,it cost a lot so it must be good,and I feel better now"
I do know Mobile One recommends against using their gear oil GL5 in synchro manual transmissions.
Another recommendation I have read "If it says MT on the label,that is manual transmission rated".OK,that is the headline.API spec....till you read the fine print.The MT designation is for non-synchro heavy equiptment.
Its an interesting topic to educate yourself on.
Unfortunately,there are far more opinions than folks who have a clue what the designations mean.
Its your Terc!! Do what makes you happy.
Like my old Volvo 544 with 4wd.I seldom regret neversieze or threadlocker
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Re: unhappy with 80w-90 gear oil

Post by Petros »

the front trans axle assembly has hypoid gears in the front diff, the gear oil is all mixed together in diff housing, main gear box, and transfer case since they are internally connected and can be filled from one filler. It seems to me it would be impossible to get a hypoid rated gear oil, that can not be used with bronze syncros if they were not compatible.
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kamiphloj
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Re: unhappy with 80w-90 gear oil

Post by kamiphloj »

Good point on the hypoid gears in the transaxle.
I don't know the answer.In any case,there is merit in being aware of the differences in the oils.
I encourage doing the research,making your own choices,and taking care of your Terc as you see fit.
No heartburn!
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Jonymoto
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Re: unhappy with 80w-90 gear oil

Post by Jonymoto »

I was reading this old thread yesterday and discovered a few have commented on GL5 oil damaging bronze synchros. Has this been proven to be correct?
When I first bought my brand new Tercel, I was finding it hard shifting from 1st to 2nd during our very mild winter (a normal winter day in Melbourne would be from 4-16 deg C) which is not anything that you guys would experience. So I took the car back to Toyota and all they did was put a thinner oil in the gearbox. Since then I've been using Castrol Multitrax 80W-90 API GL5 oil for this very reason. As of yesterday I didn't realise GL5 was an issue with bronze synchros. The car is now 32 years old and I haven't had any synchro issues.
Having said that, I did replace the original gearbox with a newer one about 10 years ago, not because of shifting problem, but because there was a bearing noise in the gearbox and at the time it was easier and cheaper for me to replace the box with a used one from Japan. I wish I had kept that old gearbox now, had I known I would still be driving this magnificent Tercel and Xirdneh would be posting youtube videos.

I've also been using this oil in my wife Rav4 over the last 8-10 years. Now I'm getting concerned about the harm I've been doing to those synchros. :shock:
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Re: unhappy with 80w-90 gear oil

Post by 4wdchico »

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
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My tercel:: 1983, DLX 4wd wagon with 4.1 manual gearbox, tow bar). Manual steering. 313,000 kms. Tercel 4WD SR5, 1987, 500,000kms. Other car - 2003 Rav4, AWD, 2l manual, Peugeot 407 Diesel (93,000 miles) in Ireland for use when on holiday there.
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Re: unhappy with 80w-90 gear oil

Post by Jonymoto »

Oh man, now I'm very very confused. I just changed the oil in my transaxles from GL5 to GL4 last Saturday to try and save my synchros from any further GL5 erosion.
When you lose, don't lose the lesson - The Dalai Lama
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