Re: BigKev's 1954 Packard Clipper Deluxe Sedan

Posted by Ross On 2016/4/18 5:36:58

That mod with the slots is not necessary on any 56 I have seen, but I guess it couldn't hurt.

But I do find this important for low-high shift quality: The original discs (used in Hydramatics as well), were slightly waved. This bow in the disc helped them engage smoothly as they flattened out under pressure, but it also meant that they took up a little extra space in the stack. The modern discs are dead flat and will make your stack a little shorter. That means that extra fluid has to be pumped into the clutch before it engages. That takes but a moment of time, but by then the low range band has long since released and engine revs are climbing. The result is a harsh shift.

Two things I like to do that give a very nice shift: First, I like to use a mix of the old waved and new flat discs to get a little bit of cushion action. If I have them on hand, I alternate them. Second, I make sure that the clutch pack is full. By that I mean that the stack comes up to just below the shoulder where the rear cover sits. If I mix waved and flats, I usually have to lay on an extra steel to take up space. If using all flats, I can get in an extra flat and an extra steel. Be sure to use lots of fluid during the assembly so there is something between the discs when the unit is idling in neutral on initial startup.

I would like to mention that there is nothing wrong with the original style discs. Failure only occurs with excess slipping, and that problem always come from elsewhere.