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

So it seems what is wanted is partial throttle kickdown. Well, for sure the 54 Ultramatic in my roadster doesn't do it. How stupid of Packard. But by the way, neither does the excellent Detroit Gear automatic in the 53 Commander. Or the Borg Warner in the 58 President. Or the early Hydramatics I've driven. It seems the design philosophy was to make kickdown only a conscious choice in cars with plenty of low speed torque. In normal driving one just powers away from the slow spot unless there is a good reason for a little more drama.

One of seldom noticed innovations of the Gear Start and newer Ultramatics was that kickdown out of direct was affected by the speed the gas pedal was moved. Thus when I come to the slow uphill curve in a V8 car I flutter my foot on the gas so it won't lug. In an earlier car I plunge the gas ever so briefly to the floor and return to a suitable throttle position for the curve. Somehow this has never registered with me as a problem.

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Thanks for your input. I suggested this earlier but was not certain this was the correct technique.

I need to go for a drive tomorrow and do some experimenting! After rereading the excerpt I posted from the service manual, my issue may be that I need to depress the gas pedal more than I have been in order to get the direct drive to disengage. It says "when the accelerator is pressed BEYOND full throttle position." This would explain why Ross' plunging technique would work.

Is this the reason the linkage to the carb is spring loaded? So that at full throttle there is more travel in order to move the throttle valve to the position needed to release the pressure to disengage the direct drive?

My approach has been to not to floor it when the direct drive was engaged at low speeds and allow my car to slowly get going, always being gentle with my car. But maybe that's my problem, I need to floor it "beyond full throttle", at least momentarily, to get the direct drive to disengage??

Is this correct? The "typical" working range of the throttle valve regulates when the direct drive will engage, but for the throttle valve to disengage the direct drive, it has to go beyond the typical working range, that is "beyond full throttle."

This may be what has been said and it's only sinking in now.

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Hi again
The DD cluch was deemed ok and was not replaced. Did Ross mention whether what I experience is "normal operation" or not? I now see that his 54 Sportster works the same stupid way as my 54 Panama, but do we have to consider this operation "Normal"? Don says it is definitely not. Is it just an issue on 1954 models?
Greetings, R

53 Cavalier wrote:
I need to go for a drive tomorrow and do some experimenting! After rereading the excerpt I posted from the service manual, my issue may be that I need to depress the gas pedal more than I have been in order to get the direct drive to disengage. It says "when the accelerator is pressed BEYOND full throttle position." This would explain why Ross' plunging technique would work.

Yes, as I also mentioned previously: "What I would suggest you try is to get in the habit where, if you want the direct drive clutch to disengage, quickly press the accelerator pedal to the floor just long enough that the transmission disengages the clutch, then release it most of the way. With some practice, I think you will be able to do this to get out of direct drive, without having a dramatic response from the engine. If you find success with this, you may also be able to adjust the throttle linkage back to the usual position, so that direct drive engages earlier." (The last sentence applies to Roland specifically, since he adjusted his linkage out of spec earlier.)

And Ross's synonymous comment was: "In an earlier car I plunge the gas ever so briefly to the floor and return to a suitable throttle position for the curve. Somehow this has never registered with me as a problem."

Is this the reason the linkage to the carb is spring loaded? So that at full throttle there is more travel in order to move the throttle valve to the position needed to release the pressure to disengage the direct drive?

Yes.

My approach has been to not to floor it when the direct drive was engaged at low speeds and allow my car to slowly get going, always being gentle with my car. But maybe that's my problem, I need to floor it "beyond full throttle", at least momentarily, to get the direct drive to disengage??

Yes.

Is this correct? The "typical" working range of the throttle valve regulates when the direct drive will engage, but for the throttle valve to disengage the direct drive, it has to go beyond the typical working range, that is "beyond full throttle."

Yes, that is exactly the intended operation. The throttle valve regulates essentially in proportion to the throttle opening, but once you are at full throttle you can hit it even harder to enter "kickdown" mode. So, they decided to design the DSV to have a 1:1 comparison of throttle vs. governor pressures when you are in converter drive, but add an inner valve and dowel that acts on the outer valve when you are already in direct drive, requiring "kickdown" levels of throttle pressure to overcome, and only up to a point (i.e. you can't disengage the DDC after 50 mph).

This may be what has been said and it's only sinking in now.

Roland Irle wrote:

Did Ross mention whether what I experience is "normal operation" or not?

Yes, he mentioned that this is normal not just for the Ultramatic, but also for other transmissions of the time.

I now see that his 54 Sportster works the same stupid way as my 54 Panama, but do we have to consider this operation "Normal"? Don says it is definitely not.

Hopefully Don can elaborate on his experience.

Is it just an issue on 1954 models?

No, the same valve was used 1950-1954.

On the definition of "normal operation", the owner's manual states:

'"H" means HIGH range. This position is used for all normal forward driving.
When driving below 50 miles per hour in the high range, extra power for quick passing of another car can be had by pressing the accelerator pedal firmly down against the floor. '

This provides less information than the service quote provided by 53Cavalier in entry #19, but the target audience is different.

HPH: What source are you referencing for your valve/piston sizes in entry #6, or is that answered by your picture in entry #19?

Roland: Were the pressure tests you ran those in the service manual, or did you do others related to this issue?

We have had a great discussion on the theory of operation, but are lacking actual data for this specific issue.
Charting the actual pressure data similar to HPH's chart in entry #20 would be a good start. Of course, you would want to also include speed and pump and direct drive pressures at a minimum in the data set.

I collected pages of pressure data in order to make my adjustments.

Found this in the Ultramatic Training Manual. I wish it would really work this way ...

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My micrometer.

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There is nothing incorrect about this statement, it just does not explain the nuances of operation. ALSO, this was written before the valve which we are all talking about, was introduced. The very first design worked a bit differently.

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I want to hear from Don again! Maybe his cars are the same as ours, and the difference is he knows how to drive them!

On another note, if the DD clutch is not replaced, and hasn't been replaced previously, then using modern ATF is a no go, correct? That is, the material used to make the clutch are not compatible with modern ATF. Is that correct? Are clutches expensive? Does it not make sense to replace this wear item if you have your torque convertor apart? I would have assumed the answer is yes, but maybe I'm mistaken.............it's happened before!