Re: Ultramatic

Posted by HH56 On 2024/6/13 16:04:37

Quote:

Agree. As long as you remove power while it shifts and don't try to rush things it will be tolerable. Problem with original Ultras is there is NO synchronization between low and high range. It was meant to operate in one or the other. When doing the manual shift, it is usually because you want a faster take off to keep up with traffic so too often it was done under power and shift was done quickly as the car gained speed. Using a bit of decorum and letting the car coast as you wait for the trans to do its thing defeats the whole purpose of the manual shift.

Issue becomes sometimes low would fully release before the high range clutches would begin to lock together so with nothing connected to the wheels the engine would race and then the clutches took all the load and slipped resulting in heat and wear as they tried to bring the engine back to normal speed. Other times it would be the opposite and high would lock up before low even started to be released. That usually resulted in a serious lurch and horrible strain on internal pieces as the two gears tried to work at the same time. Either situation under power could result in some interesting noises and operation.

Packard did try to bring this under better control in late 53 with the introduction of a timing kit and again in 54 with a revision to the timing kit. The kit changed a valve and spring and a small pin was used to restrict flow in a passage to better control part of the shift but this was only partially successful. The late 54 Gear Start was the first transmission from Packard designed to do a L - H - DD shift. Unfortunately it had a serious lack of actual field testing and driving before being put behind a high horsepower V8 and we all know how that worked out.

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