Diff / Trans / steering box fluids

[Tom Devoe]

OK - as I move along with the 1931 six, I'm finding lots of information and mis-information about what fluids to use in these old cars.  Can anyone shed some light on what they use in their cars in the late 20's early thirties era, and if they're happy with the results?  My car may still have really old fluid in these 3 areas, and right now I won't be rebuilding any of the assemblies, so the fluid should be compatible with what's in there now.  My transmission is the free wheeling design, so that may affect what fluid I use too.

Right now it's very confusing, and I've seen anywhere from original gear lube found at an auction to STP, with 90w G-L1 & 600w black oil somewhere in the middle.  Thanks for any light you can shed on this!  I'd appreciate real world experience!

Tom

[Spinneyhill]

Steering box is the easiest. Use a semi-fluid grease, NLGI 00. Heat the bottle up a bit before attempting to pour it!

 

I don't think free-wheeling should affect it, other than any brass being in there. You may have brass inside the countershaft (a.k.a. cluster) gear in the gearbox too. Most say avoid GL-5 gear oils because the EP additives may attack brass. The Copper Strip Corrosion Test will indicate if that happens. You want a 1a result - it should be on the tech sheet for the oil.

 

These oils are the subject of many questions. If you search the fora, you should find plenty of information. Here is one, in the Buick forum: p. 12 and 13.

 

Edited September 18, 2018 by Spinneyhill (see edit history)

[1927Chevy]

here is a link for some 600w, bottom of page 

 

https://www.fillingstation.com/catalog/flippingbook/files/assets/basic-html/index.html#325

[keninman]

Was the reason for the really thick lubricants because the seal were nearly non-existent? I also wonder about how modern lubricants might affect any rubber seals as well as the brass or copper in these components. Only recently did I learn of how corrosive that modern antifreeze is, still I don't intend to pour in alcohol or kerosene. 

[Spinneyhill]

5 hours ago, keninman said:

I also wonder about how modern lubricants might affect any rubber seals as well as the brass or copper in these components. Only recently did I learn of how corrosive that modern antifreeze is, still I don't intend to pour in alcohol or kerosene. 

NO lubricant will damage rubber seals. Seals are made to resist them, else why would you use the seal?

 

Some EP additives attack copper and copper alloys, not all. Any oil having an EP additive should have the Copper Strip Corrosion Test results in its tech. data. As I said above, a 1a result is what you want. 1b is ok, but not as good.

 

Modern antifreeze is NOT corrosive. That is a myth. It probably arose from a case in the '80s when GM (?) had some manifold gasket problems with an antifreeze. I have put this up on these fora before. There is one chemical often used in AF that does attack one of the materials used in seals. e.g. Penrite's antifreeze (from BASF) uses it. But it is masked by other chemicals. Penrite say their AF will not attack any seal or metal or gasket.

Edited September 29, 2018 by Spinneyhill (see edit history)

[keninman]

I would have to respectfully disagree about the antifreeze. There is too much information about it loosing its corrosion resistance and actually causing corrosion if it is not changed at recommended intervals. In my 29 Stude the thermostat spring had completely rusted away in spots. Also when I pulled he water jacket cover I found a great deal of scale which I flushed out. 

 

https://www.cars.com/articles/how-often-should-i-change-engine-coolant-1420680853669/

[Spinneyhill]

Yes, of course. If you don't use a product as it is designed to be used, it can be harmful. The older types should be changed at 2 to 3 year intervals, for the reason you give. OAT bottles claim the contents to be good for 5 to 7 years. But other than being harmful to paint, new antifreeze is not corrosive.

 

I suppose it is like oil. It only lasts so long before the additives are used up. It seems to me we must be assiduous in changing at nominal end of life any product that has constituents that can be damaging but are masked by others to prevent that damage. You might like to think about grease containing molybdenum disulphide, which is corrosive - they all contain anti-corrosion additives! All these additives are used up in doing their work.