Packard Forum Index » Post-War (1946-54)

HH56 wrote:
The 53 has what is considered the regular or original Ultramatic. For driving purposes, it is essentially a one speed transmission with torque multiplication in the converter. When you select H it starts and stays in high range with the direct drive lockout of the converter occurring starting somewhere around 20 mph depending on throttle position. If the driver is heavy on the pedal the more throttle and the direct drive engagement comes in at a later speed. Below about 50 a quick depression of the accelerator will drop it out of direct drive back into converter drive but it is still in high range. Anytime the car is going above approx 50 mph the direct drive will not drop out with the quick depression.

The timing of the direct drive engagement is highly dependent on the correct adjustment of the throttle linkage and that resulting pressure. Other pressures controlled by the throttle pressure also influence how tightly the high range clutch plates are clamped together. Too low a pressure and the high range clutches can be subject to slipping and burning.

Low range works exactly the same way except the car starts and stays in low range.

There is no synchronized timing between low and high range so the practice some have gotten into of starting in low and manually shifting to high is not recommended. Done under power the low band can release before the high range clutch applies letting the engine race and rely on the high range clutch plates finally grabbing and slowing the engine or the low range band and high range clutches can both be in at the same time causing a tremendous strain. Either situation can result in possible damage in the transmission. If a driver does insist on the manual shift let off the accelerator and wait for the transmission to complete the shift before re-applying power.

Packard did try to address this issue with the availability of an improved timing kit for the 54 models and made that kit retroactive to earlier units if the customer wanted to buy it but it was not completely successful. In late 54 they introduced the gear start Ultramatic -- later called the Twin Ultramatic -- which in one driver selected range worked as the original, and in another driver selected range did shift from low to high to direct drive and was capable of downshifts.