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Hello. I'm in the process of changing transmission fluid. Can someone tell me what the equivalent fluid would be for my ultramatic. The manual says type A or AQ. Another sight said type F was the modern equivalent, but wanted to make sure. Also, is there anything else I should know before dropping the plugs. Thank, Brian

Type F is the closest modern equivalent and is to my knowledge what the majority of folks use in their Ultramatics. Type FA is also a reasonable equivalent to the original Type A. Though it may give "softer" shifts the Ultramatic was designed to use fluids which did not contain "slip agents" such as used in Dexron etc. though many folks report satisfactory performance with such fluids.

yes, Type F is the closest to the original fluids. I have many Ultramatics running on Dextron as well. Dex does tend to shift smoother than F, however F tends to hold clutch chatter down more with the Raybestos materials.

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I'm very confused here. Ford didn't release or use transmission fluids without friction modifiers until 1961, long after Packard had left the business.

Packard spec'd Type A, which IS a friction-modified fluid.

Type A, which was a specification developed by General Motors for their own automatic transmissions originally released in 1949, used sperm whale oil as a friction modifier or "slip agent" as you call it. It wasn't the greatest of fluids - it degraded quickly, it had a low shear strength, it was prone to viscosity breakdown, etc. When its oxidation performance was upgraded in 1957, the specification became Type A/Suffix A, which became somewhat the world standard until the standard was upgraded further and renamed Dexron in 1967. The Dexron line is the successor to Type A, as far as I can tell, and even General Motors has specifically declared that Dexron III is backward compatible with all previous Dexron specifications back to Type A.

So at a minimum, it's debatable whether Type F is the closest modern equivalent to Type A -- because the Type F spec hasn't been revised since 1967, it probably is more closely comparable to the original Type A fluids in that the standard sets relatively low limits on oxidation performance, viscosity stability, wear reduction, heat breakdown, etc.

It is, however, generally accepted that using Type F in a transmission originally designed for a friction modified fluid (as Ultramatics were) will not do any real harm other than firming up the shift quality. However, friction modified fluids should never be used in a transmission that was designed to take Type F -- it will destroy the clutches in very short order.