RE: {Chrysler 300} Type A auto trans fluid for PS?

["Rich Barber" <c300@xxxxxxx>]

My Copilot says this in answer to my query.  The query included a question to Armour & Co. as I recall reading a reference to Armour as being the original manufacturer/packager.

🛠️ Type A Transmission Fluid: Origins and Evolution
Type A automatic transmission fluid (ATF) was introduced in the late 1940s, coinciding with the rise of automatic transmissions in American vehicles—particularly General Motors' Hydra-Matic systems. It was the first standardized ATF and was formulated to meet the lubrication and hydraulic needs of early automatic gearboxes.
📜 Historical Highlights
- 1949: General Motors released the first service-fill specification for ATF, known as Type A.
- 1950s–1960s: Type A became the industry standard for many domestic vehicles, especially GM models.
- Suffix A: A refined version was later introduced to improve oxidation resistance and seal compatibility.
- 1970s onward: Type A was gradually phased out and replaced by Dexron fluids, beginning with Dexron I and evolving through Dexron VI.
🧪 Composition and Characteristics
- Mineral oil base with early additive packages.
- Designed for low-pressure hydraulic systems and basic friction control.
- Not suitable for modern transmissions due to changes in metallurgy, seal materials, and performance demands.
🧯Modern Replacements
- Dexron III(H) and Dexron VI are considered backward-compatible replacements.
- Some industrial users substitute AW46 hydraulic fluid or power steering fluid for legacy applications.

🔍 Armour & Co. Connection?
There’s no direct evidence in the available sources linking Armour & Company—a meatpacking and chemical firm—to the original formulation or distribution of Type A ATF. However, Armour did produce various industrial chemicals and lubricants in the mid-20th century, so it’s plausible they may have been a supplier or private-label distributor of transmission fluids during that era. If you’re tracing a specific can or label, I’d be glad to help document it further.
Would you like to explore vintage packaging or trace a specific Armour product?  I then asked about the whale oil issue and they responded: 

🛢️ Whale Oil in Early Transmission Fluid? A Curious Truth
The suggestion isn’t just folklore—it’s historically accurate. Early formulations of Type A automatic transmission fluid, particularly those used by General Motors in the 1950s and 1960s, did indeed contain sperm whale oil as a key additive.
🐋 Why Whale Oil?
- Lubricity & Anti-Rust: Whale oil offered excellent lubrication and rust-prevention properties, especially under the relatively low-pressure, high-heat conditions of early automatic transmissions.
- Thermal Stability: It performed well at high temperatures, making it ideal for hydraulic systems before synthetic alternatives were developed.
⚠️ The Turning Point
- By the early 1970s, the use of whale oil was discontinued due to environmental concerns and the endangered status of sperm whales.
- GM and other manufacturers had to reformulate their fluids, which led to corrosion issues in some systems until better synthetic blends were developed.
So yes, the original Type A fluid likely had “a little whale oil”—not as a novelty, but as a functional and widely accepted industrial ingredient of its time. If you're tracing a specific can or label, especially one from Armour & Co., it might be worth checking for product codes or chemical disclosures that hint at this legacy.
Would you like help drafting a short archival note or provenance tag for a container that might reference this?

Respectfully submitted,

Call me Ishmael

-----Original Message-----
From: 'Keith Langendorfer' via Chrysler 300 Club International <chrysler-300-club-international@xxxxxxxxxxxxxxxx> 
Sent: Sunday, August 3, 2025 7:56 PM
To: Club International Chrysler <chrysler-300-club-international@xxxxxxxxxxxxxxxx>
Subject: {Chrysler 300} Type A auto trans fluid for PS?

Folks

So, the original factory recommendation for the Power Steering reservoir on my ‘56 Golden Hawk (sorry!) says “Type A”. I’m guessing other similar vintage Letter Cars called for the same so was wondering what you used in lieu of the old Type A? Dexron/Mercon? 

I think most of the newer fluids are probably backwards compatible, especially for a PS pump, but wanted to poll the group. 

Sorry if I’m missing the obvious!

Thanks, 

Keith 

-- 
For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang
--- 
You received this message because you are subscribed to the Google Groups "Chrysler 300 Club International" group.
To unsubscribe from this group and stop receiving emails from it, send an email to chrysler-300-club-international+unsubscribe@xxxxxxxxxxxxxxxx.
To view this discussion visit https://groups.google.com/d/msgid/chrysler-300-club-international/B67BA31C-B572-42D5-A644-98872077B406%40yahoo.com.

-- 
For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang
--- 
You received this message because you are subscribed to the Google Groups "Chrysler 300 Club International" group.
To unsubscribe from this group and stop receiving emails from it, send an email to chrysler-300-club-international+unsubscribe@xxxxxxxxxxxxxxxx.
To view this discussion visit https://groups.google.com/d/msgid/chrysler-300-club-international/018101dc0578%24263341a0%247299c4e0%24%40ez2.net.