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proper oil for bw overdrive

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Forum Name: Transmission & Drivetrain
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URL: https://theamcforum.com/forum/forum_posts.asp?TID=92056
Printed Date: Mar/28/2024 at 7:04am
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Topic: proper oil for bw overdrive
Posted By: auag85201
Subject: proper oil for bw overdrive
Date Posted: Jan/24/2018 at 12:00am
i read in the overdrive manual that the only oil you can use in the bw overdrive is gl1 gear oil..but according to the tech service manual you can use 80 w. gear oil...10w 30 engine oil or atf type A...what do you guys use in your overdrive transmissions?



Replies:
Posted By: farna
Date Posted: Jan/24/2018 at 7:41am
I used 70W80 (or was it 75W85?) or something similar in the first I had, used 10W40 synthetic motor oil in the last one, which was rebuilt. I wouldn't use ATF -- it's just too thin for my comfort. Modern gear oil isn't suitable for anything with brass or bronze parts, that's why I used synthetic engine oil. Synthetic because it breaks down less and lasts longer. 

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Frank Swygert


Posted By: Lyle
Date Posted: Jan/24/2018 at 12:33pm
Frank is correct on all counts. The high mileage synthetic motor oils have higher gear shear and pressure rating usually. Look for a Cx-4 or GF-5 on the label.
I see that Castrol 10W40 high mileage is GF-5.
Don't get confused by SAE viscosity numbers for motor oil vs gear oil. 75 gear is similar to 10 motor and 90 gear is close to 50 motor. Two different systems.
Gear oil does not have detergents or other combustion related additives.  


Posted By: 6768rogues
Date Posted: Jan/24/2018 at 7:02pm
I put 80/90 gear oil in mine 35,000 miles ago and it works perfectly.

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Located usually near Rochester, NY and sometimes central FL.


Posted By: tomj
Date Posted: Jan/24/2018 at 10:39pm
as above. it's not that fussy. i experimented with lighter oils (10w30) ended up with 90 weight gear oil.

as mentioned some have additives that eat bronze -- but careful reading reveals that that corrosion is very slow! i wouldn't use it, but it's not immediately fatal.

50 weight motor oil or 85w90, the old fashioned stuff is more than adequate. if you were to change it on a 10 year schedule you'd be insanely ahead of the game :-)



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1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com



Posted By: Mr_AMC
Date Posted: Mar/13/2018 at 10:44am
SO?? I just got a Twin stick car.. From reading .. Guessing that there is bronze in the OD unit??   Best oil to use would be????? Do synthetics NOT have the bronze corroding additive??
Thanks..


Posted By: tomj
Date Posted: Mar/13/2018 at 11:52pm
it's nearly a religious question... lol...

i used all sorts of stuff, 80/90 gear oil seems as good as anything. i used 20W50 motor oil, that was fine. 

you should avoid the most common stuff, GL3 rated or whatever, that is claimed to eat bronze. i'm sure it's true, but it will take a loooong time to eat it.

the lube in these old style transmissions almost doesn't matter. it's just a not very demanding application. it's not under tremendous sliding forces, it doesn't get very hot, little chance for contamination, etc. i think this is why there's not some great do or die decision here.

since it doesn't get very hot, variable viscosity oils like 20W-50 don't get much thinner while operating.



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1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com



Posted By: billd
Date Posted: Mar/14/2018 at 11:26am
Be careful - AMC changed specs on their transmissions several times as far as fluid. 
The real changes came in the 1980s with the T5 etc. - 
The best one I have used and I've tried almost everything over the years, is "Synchromesh" by Penzoil.
It's made specifically for the bronz or "yellow metal" containing transmissions and it made my T5 purr like a kitten and shift super-nice even in sub-zero temps. It holds it's properties and works great with synchronizers and it actually follows the AMC spec they last issued - which MOPAR continued to use. 
It matches up with what AMC recommended in the end. 
No ATF - I'd never use that i any transmission.
Yes, transfer cases do use it and that's just fine - there's no synchronizers like the transmissions use - they are different animals and go fine with ATF.
Some sites even rebuilder sites have said "10w40" etc but been there tried that. Eve AMC DROPPED THAT as a spec in later years. 

Actually it doesn't take forever to eat the bronze - that's how it's known - people tried it when it came out and it wasn't too long.........

I started rebuilding transmission at about age 15 - first, by necessity - I ate three of them racing my old Rambler. 

When you've seen as many transmissions destroyed and had the shifting experiences - and have tried several different things in the same exact transmission - I can say honestly I've done side-by-side comparisons over the years, changing fluid every few months to something different until I settled on the "Synchromesh" fluid-  and did the research on all the AMC technical service bulletins.

Do what you want,, but those synchronizers do go through heck....... and I never had as much great luck with anything else. 
I've used AFT, gear lube, several different engine oils including 50 weight racing oil and more..... and I'll never switch back to any of those ever again after the great experience I get with the AMC recommended fluid. (they called it "fish oil" because the AMC formulation stunk like heck)
I drive in temps from sub-zero to over 100 degrees - in town stop and go with tons of up and down shifting, and long highway drives. 

My Eagle gets hammered pretty hard - I am not easy on that transmission - and like I said, I tore up my first Rambler transmission three times in short order.... 

You'll get arguments back and forth - sort of like engine oil. But in this case it's based on real-world making a living at it and doing the research AMC did...... I spent months researching their documents, etc.

Just don't eat any yellow metal and do what makes it smooth and quiet........ your choice, your car.


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Posted By: farna
Date Posted: Mar/15/2018 at 5:21am
I agree with you Bill.. and Tom. The newer trannys like even the T-150 are under more stress than something like the old T-96. More power going through them and modern drivers are harder on transmissions. I'd use motor oil before ATF -- nothing that thin should be in something that is splash lubricated like a manual trans! It's different in an auto with forced lubrication and less stress on the gears (no sliding parts, and smaller gears that spread the load more). Transfer case is a chain with the lower parts always in oil. The older all gear drive transfer cases used a heavier oil. I ran 10W30 synthetic in my T-96/OD and never had an issue. It did lunch the synchros early, but more because it had a 4.6L ~250 hp stroker in front of it than anything else... The synchros in that trans are a type that don't tolerate a lot of abuse or power, and I was putting 2.5x the power of a 195.6 OHV/2V (rated 135 hp gross, which equates to ~97 hp net... 72+ ratings  are net). Almost 2x as much even with the gross ratings...


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Frank Swygert


Posted By: tomj
Date Posted: Mar/15/2018 at 10:47pm
thanks billd for the info. i'll go with your experience.

i was talking only about the old T96 of course, not anything more modern.




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1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com



Posted By: Mac VP
Date Posted: Jun/02/2018 at 8:01pm
We rebuild the Borg Warner overdrive transmissions (ie 1949-1966 types....mostly Ford based). The original specifications called for GL-1 gear oil. Over the years the refiners have made improvements in the product and it has evolved from GL2 to GL5 (which is the current spec). Some brands have included their additive package that is okay with the yellow metals (brass, bronze, copper etc) in the GL5 spec. However, unless the packaging clearly states that it’s okay with yellow metals, we recommend staying with GL4 gear oil. We stock the Sta-Lube brand in the GL4 oil. The weight is 90W. Also, I don’t recommend any synthetic gear oils......although they are great gear oils, they also tend to find every crack and crevice and you’ll end up with puddles under the transmission.


Posted By: Mr_AMC
Date Posted: Jul/23/2018 at 12:12pm
So..  Then which is best lube  in the BW overdrive Unit??   As this is the first BW overdrive I have owned..  My 75 Hornet has the Laycock one....
Thanks...


Posted By: farna
Date Posted: Jul/24/2018 at 5:21am
Same as manual transmissions -- GL4. The 75W90 stuff is fine. As noted, GL-5 is fine as long as it states it is safe for "yellow" metals (specifically bras and bronze).


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Frank Swygert


Posted By: Mr_AMC
Date Posted: Jul/24/2018 at 12:32pm
Thank you Frank..
I put in the Penzoil syncromesh fluid, as I put in the Transmission. I will have to look at the GL rating, as I don't remember..  I have a funny sound, and it SOUNDS like a twin grip rear end, which you forgot to put in the friction modifier, but I took the dif cover off, and it is an open differential.  on a jack, everything sounds quiet when I spin the wheels or the driveshaft.   Guessing I have an overdrive noise, or a differential issue..
Thanks for the help..

Jeff



Posted By: farna
Date Posted: Jul/25/2018 at 6:58am
I would suspect the outer axle bearings. Probably only make a little noise with weight on them. They are the first to go out since they carry the weight of the car. I've never had a car with worn out differential bearings that wasn't abused in some way, like run low in oil.


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Frank Swygert



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