my head and eyes hurt looking at transmission lube

[stumps]

The government would rather carry a truck loaded with barrels of GL5 SAE85W90 than a truck loaded with a little of this, and a little of that. They chose one single oil to simplify their supply line, but you use so little oil that there is no reason for you to do so.

The transmission manufacturer specified SAE50 motor oil. The transmission definitely does not need the extreme pressure (EP) additives that are needed to keep hypoid and worm gears alive in differentials. In fact, some of the EP additives contain sulfur products that will actually harm the brass and bronze bearing parts in the transmission. That is why the GL1 yellow metal safe requirement is in place.

What I intend to do when it is time to change my transmission oil is to put a nice SAE50 motor oil in it. Stinky oils (hypoid) belong in the differentials, not the transmissions.

One other thing to note: There are multiple oil standards in the SAE numbering system. SAE 90 gear oil is about the same viscosity (thickness) as SAE50 motor oil.

-Chuck

 

[Ord22]

use 90w. we use this in the military.

 

[jaxsof]

New Venture was so concerned about "yellow Metal" longevity that they specify Castrol Syntorque, at $35 per quart, for the NV4500. Totally synthetic, about 50wt. Im not recomending it for something it wasnt recomended for. However, Castrol (Europe) seems to be beating us(read the US) in lubrication technology. There you can get SMS-X which is GL1-4 (no sulfur).
As the EPA is sooo anti sulfur with out fuel, why are we lagging in this? Sulpher, btw is the stuff that destroys brass.

AMSOil SAE50 is synthetic, and GL1.

The "synthetic oil causes leaks" myth seems to stem from Arco Graphite, which, some of us older guy will remember, was really BAD stuff. I prefer synthetics because they are more uniform in their composition, and dont accept contaminants as readily as mineral oils. Just a personal preference though.

Mercedes and Cat still recomend GL1 for their heavy transmixers.

Please pardon the scatter-brained post. I hope it has some information that helps some of us.

 

[m16ty]

New Venture was so concerned about "yellow Metal" longevity that they specify Castrol Syntorque, at $35 per quart, for the NV4500.

I thought the NV4500 had fiber sycros and not brass.

 

[m16ty]

IMO, most of this thread is about solving a problem that doesn't exist. There is no problem that I'm aware of that is caused by using GL-1. These trans rarely fail and the ones that do were more than likely caused by abuse by young soldiers while in the military hands. Why not just use GL-1 and be done with it?

I know people say that there are better oils out there but I haven't seen one bit of evidence that running something other than GL-1 will make the trans last longer. I have seen evidence that if you run the wrong stuff it can cause problems. These trans will run forever with GL-1 in them as long as you don't abuse it (shifting without the clutch, slamming it into gear, and such) or it hasn't been abused too much in the past and is on it's way out anyway.

I would just stick with either GL-1 (what the military calls for) or 50wt engine oil (what the trans manufacturer calls for).

 

[Flyingvan911]

I just bought some Valvoline 80W90 from NAPA. It is MT-1/GL-5 and meets the Mil-Spec. That's good enough for me.

 

[pvtjorge]

I went NAPA to look for transmission oil. they didn't have 50wt motor oil on the shelf, but said they could order it and it would be there the next day. I went back the net day, the clerk opened up the case they ordered and I purchased 5 qts. for my jeep.
so if they don't have on the shelf what you want ask them to order it.

 

[dkeven]

NAPA part 65-205 is their GL1 and they either have or can get it readily that's what I went with

 

[doghead]

Steel Soldiers::Military Vehicles Supersite - Search Results

 

[Wildchild467]

I had 80w-90 in my transmission and it did not shift good at all. I pulled the top off the tranny and looked at it and the synchros are buggered up some from the last GI that drove it im sure. Then i did some research on here about it and switched to 90w GL-1 from Tractor Supply. Its the stuff thats recomended in Ford tractors. Anyway, it shifts A LOT better! Allthough it does not put brass back on the synchros, its way better... now i dont know if i should put new synchros or buy another transmission to throw in it...what would be easier. I dont live far from Kublos...so i dont know what would be better price wise...any advise??

 

[m-35tom]

in the long run any oil you use from 30wt motor oil to 90 wt gear oil will be fine. i found that i had to use 40 wt motor oil in my transfer case to solve a problem. the 90wt oil would foam so much that it would blow out of the vent at speeds near 70. (in my last truck, cat powered with .66 OD) typically the trans runs at 150º to 160ºF.

my 2¢

tom

 

[Wildchild467]

the only thing i worry about with using a motor oil is that motor oil does not have the additives in it to make the gears happy. Its like motorcycles having special motorcycle oil because the engine oil and transmission oil is all the same, therefore there are special additives to make the transmission in the motorcycle happy too. I had an '84 honda and when i did the first oil change i just put regular engine oil in it. the result was that it did not shift as good as when i first got it. I then changed it and put motorcycle oil in it and it shifted a lot better. I respect whatever anybody wants to put in their transmission, i just like something that is made for gears too..... so maybe what about using like a 20w-50 motorcycle oil?

 

[stumps]

the only thing i worry about with using a motor oil is that motor oil does not have the additives in it to make the gears happy. Its like motorcycles having special motorcycle oil because the engine oil and transmission oil is all the same, therefore there are special additives to make the transmission in the motorcycle happy too. I had an '84 honda and when i did the first oil change i just put regular engine oil in it. the result was that it did not shift as good as when i first got it. I then changed it and put motorcycle oil in it and it shifted a lot better. I respect whatever anybody wants to put in their transmission, i just like something that is made for gears too..... so maybe what about using like a 20w-50 motorcycle oil?

You are worrying too much. The transmissions were designed back in the days of yore before all the special additives were even thought of. The manufacturer recommends SAE50 engine oil, or straight SAE90 gear oil, without the EP additives,... just like a tractor. The EP additives can contain sulfur compounds which are hard on brass and bronze.

Engines have all of the same internal frictions as do geared transmissions. Engines need a little more help because of the combustion products that find their way into the oil.

I used plain old Castrol 20W50 oil in my bikes for years and years without a single problem.

-Chuck

 

[Tinwoodsman]

I agree. I just picked up two gallons of NAPA GL-1 today for $9 per gallon. I sure my tranny will love it.

 

[jaxsof]

m16ty, you are absolutely correct, however, the same stuff kills brass, kills them(even faster). Good Catch. I was half asleep at the time.

Umm, GL5 is a sulpher containing oil formulated for hypoid gears(differentials usually with LSD's)

GL4 has replacer GL1-3 which are "inactive"

1995 API Categories GL-1, GL-2, GL-3 and GL-6 were declared inactive by SAE Technical Committee 3.

Hey, it is a heavy beast, but if you want to R&R it to replace those little brass rings, like the man said, it is your vehicle.

 

[dkeven]

I had 80w-90 in my transmission and it did not shift good at all. I pulled the top off the tranny and looked at it and the synchros are buggered up some from the last GI that drove it im sure. Then i did some research on here about it and switched to 90w GL-1 from Tractor Supply. Its the stuff thats recomended in Ford tractors. Anyway, it shifts A LOT better! Allthough it does not put brass back on the synchros, its way better... now i dont know if i should put new synchros or buy another transmission to throw in it...what would be easier. I dont live far from Kublos...so i dont know what would be better price wise...any advise??

Having just gone through my trans and checking it out per the tm and replacing the 4th 5th synchro I would opt for fixing yours, they are not bad to work on and as stated by others, I could have pulled the mainshaft without removing from the truck, I had a replacement lined up if needed but after seeing what little was bad opted to repair my original. just heavy is all