Quote:
Owen_Dyneto wrote:
Type F is the closest modern equivalent...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.
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.
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