80w-90 GL-4 For a 1945 Ford 2N

[John With Beastly 302]

I have known for some time now that what is supposed to be run in these old 1939-1954 N Series tractors is a GL-4 rated gear oil. And the reason is because there is brass in the trans or hydraulics right? And a GL-5 rated gear oil contains some kind of additive that causes damage to the brass. Now what is this additive in the GL-5 and what happens to the brass when the two mix? A chemical reaction?

Also what type of additives does the GL-4 gear oil have?

The reason I bring this up is that I have run both Mobil 424 Hydraulic Fluid and Valvoline 80w-90 GL-4 and currently there is 424 in my old 2N (Which I restored in a Chevron Lubricants High School Competition 9 years ago) and I'm going back to the 80w90 because the hydraulics pick up my big old heavy 3 point disc better on the 80w90. I was curious as to what exactly happens with the GL-5 and the brass.

 

[MBS500]

As I remember 5 has twice more additives that 4 and it will be corrosive for brass parts.

 

[grndslm]

Yes, there is a chemical reaction, of course. What it is, exactly... I do not know.

I think there are various EP additives (sulfate, phosphate, borate), and I also think the first two are the worst if you want a happy GL-4 gearbox.

People say that the dual-rated GL-4/GL-5 stuff is OK... but just before I decided to put some Valvoline High Performance 80w-90 Gear Oil in my GL-4 loving Nissan transmission, I decided to check out their site that I just linked to and found this "Product Info" PDF --> http://www.valvoline.com/pdf/high_performance_gear.pdf

This is what it says...
Quote:
Valvoline High Performance Gear Oils meet or exceed API Services GL-5 and GL-4*.

...

*In synchronized manual transmission applications use:
• Valvoline Professional Series Manual Transmission Fluid or
• Valvoline Synchromesh Manual Transmission Fluid (available September 2012)


So, if Valvoline's dual-rated gear oil isn't safe for synchronized manual transmissiions, then I don't know what to believe!!! The only thing that I can offer is to stick with the GL-4 only solutions, like Amsoil and Red Line.

The whole "chemical reaction" problem boils down to what will happen when these GL-5 additives meet water!! For an older tractor, I would not want to take the risk of knowing any more about this chemical reaction and would just stick to the GL-4 only solutions.

 

[Rand]

you are assuming abit much

the reason could be it just messes up the shift feel in a MT if you use the dual rated gear oil.. not that it corrodes them or is "unsafe"

 

[default]

I was under the impression these used a straight 90wt GL-1 mineral oil. http://www.tractorsupply.com/hydraulic-f...-2-gal--0806600

 

[John With Beastly 302]

Originally Posted By: default
I was under the impression these used a straight 90wt GL-1 mineral oil. http://www.tractorsupply.com/hydraulic-f...-2-gal--0806600


Well if I remember right thats what they came with from the factory back in the 1939-1954 era. But I don't know much about additives and what a GL-1 oil has vs a GL-4 I would think the additives in the GL-4 offer some benefits over the GL-1. I don't think there even was a GL-4 available back in 1939-1954. Any way thats just my presumption and I don't know for sure.

 

[MolaKule]

Quote:
As I remember 5 has twice more additives that 4 and it will be corrosive for brass parts


Not twice the additives; different types of additives and different additive "levels."

GL4 fluids for manual transmissions contain Anti-Wear Additives which contain about 400 ppm of phosphorous and lower zinc, with a bit of sulfur. The sulfur is "buffered", which means there is a special chemical added to keep the sulfur from becoming acidic and attacking copper alloy (brass) parts, but still be effective to prevent wear.

If the original viscosity was a 90 weight, I would highly recommend a GL4 equivalent MT fluid such as Amsoil MTG or Redline MT-90.



GL5 lubes main application is for hypoid differentials and contains high levels of a primary Extreme Pressure (EP) agent that contains sulphur/phosphorous chemicals. The sulfur here is also "buffered", which means there is a special chemical added to keep the sulfur from becoming acidic and attacking copper alloy (brass) parts, but still be effective to prevent extreme pressure problems such as galling, etc.