Re: The History of Packard

Posted by Rusty O\'Toole On 2009/2/10 22:45:42

On the automatic transmission question:

GM had the first automatic transmission on the market by a major US auto maker. There were efforts in this direction by the English Lanchester (Fluid Flywheel model) and I think Reo and possibly others. But GM deserves credit for the Hydramatic, in 1937 Oldsmobile and 1938 Cadillac models.

At that time the torque converter had not been invented. The fluid coupling was the last word. So the Hydramatic used a fluid coupling which would slip but would not multiply torque. Therefore they needed the multi speed gear. For certain technical reasons planetary gear sets work better for automatic shifting than sliding gears and planetary gears come in 2's so they used 2 sets for a total of 4 speeds.

Chrysler followed suit in 1939 with their own fluid coupling, combined with a 3 speed manual transmission. Shortly thereafter they brought out a 4 speed, automatic shifting sliding gear transmission. It had a 2 speed High range for all normal driving and another 2 speed Low range for slow going, or heavy going such as snow, sand or mud or when starting off on a steep hill.

A short time later,in the mid 40s, someone invented the torque converter. It has the advantage that it will multiply torque the same as a gear set.

This advance hit the automotive world like a thunderbolt. For the first time it was possible (in theory) to eliminate the transmission entirely and make a gas car that was as smooth as an electric or steam car, with no clutch and no shifting at all.

The Buick Dynaflow, Chev Powerglide and Packard Ultramatic were all efforts to make the "perfect" shift free drive. It wasn't quite possible to eliminate shifting entirely, they had a low speed for emergency use but for all normal driving they were smooth and shift free.

This was considered the ultimate accomplishment at the time, smoothness silence comfort and convenience being more important that performance or economy.

For the tightwad, or the performance addict, the manual transmission remained an option.

So in the context of the time the Ultramatic was a better more up to date transmission than the Hydramatic or Fluid Drive.

The Fluid Drive was awkward to drive but had the advantages of simplicity, rugged construction, and being more familiar in operation to those who had grown up with manual transmissions which back then was everybody. It was also possible to get a better performance out of them with a few simple tricks.

So at least in the late forties and early 50s, the Ultramatic was the leading edge design. This did not change until Chrysler introduced the first 3 speed torque converter transmission in 1957, the Torqueflite.