Mineral Gear Oil

dr deuce · Post by **dr deuce** » Mon Nov 10, 2008 3:18 pm

I just came back from a Tractor Supply store that is new to this area and they have just about everything in there!

One item that caught my eye was mineral 90w gear oil for old Ford tractors right next to the standard 80-90w new stuff.

I had mentioned in here before how I had found that with older US mil surplus GO that my rear rear pinion seal stopped leaking completely compared to a fair amount when I used the modern GO.

My question: Does anyone know anything about the mineral GO for old Ford tractors?

SpookyDad · Post by **SpookyDad** » Tue Nov 11, 2008 11:38 am

I came across an article about overhauling a hydrovac on www.stovebolt.com . The author specifically recommends using mineral oil on all the parts inside the hydrovac. I don't know about ford tractors but this seems to support the use of mineral oil.

Neil

Barry Churcher · Post by **Barry Churcher** » Tue Nov 11, 2008 7:30 pm

The transmission fluid in an “N” series Ford tractor lubricates the transmission, differential, PTO and hydraulic pump drive.
The owner’s manual for the 9N and 2N models specified the use of two fluids. They were STRAIGHT MINERAL OIL SAE 90 (above freezing) and STRAIGHT MINERAL OIL SAE 80 (below freezing). In 1950 the 8N was the only Ford tractor, oil technology had advanced a bit, and Ford specified the use of “Mild EP GEAR OIL conforming to Ford specs M4864A (SAE 80) (below freezing) or B (SAE 90) (above freezing)”
The original specification for STRAIGHT MINERAL OIL would conform to the present-day API gear oil designation of GL1. Ford M4864 “mild EP GEAR OIL” GL3 contains some Extreme Pressure additives (sulphur and phosphorus compounds) which make it a better lubricant for transmissions and for bevel-gear final drives where there is high-pressure sliding contact. The EP designation refers to contact pressure between moving parts. If you use a GL5 in some gearboxes, the GL5 additives can eat the brass synchro rings and other brass parts when they get hot. The gear oil grades are as follows with GL standing for gear lubricant and the number standing for the amount of EP (extreme pressure) additives in the oil. GL1-GL2-GL3-GL4-GL5-GL6. As far as I know GL1 only has an anti foaming additive.
Barry

dr deuce · Post by **dr deuce** » Thu Nov 13, 2008 2:19 pm

-1

Translation?

I saw that on the web too.

Does that mean you can put that in a Chev-GMC diff?

Barry Churcher · Post by **Barry Churcher** » Thu Nov 13, 2008 9:17 pm

"GL3 contains some Extreme Pressure additives (sulphur and phosphorus compounds) which make it a better lubricant for transmissions and for bevel-gear final drives where there is high-pressure sliding contact."

Yes it can be used but better is GL3 which is not as readily available. In my opinion GL5 which is the most common has too many additives for older vehicles. I have played around with different lubricants for many years, just experimenting with different applications and have had interesting results. Right now I am using SAE50 oil in the transmission of my DAF. SAE50 has the same viscosity as 90 gear oil and it works real well for me. It even shifts smoother. I used it because of its absence of additives that deteriorate yellow metal. I don't really think that makes much difference in our applications where the vehicles are not driven all that much and normally not under harsh conditions. I don't like synthetic gear oil in the old stuff. On newer vehicles such as the family car it is very important to use the manufactures recommended fluids.
Barry