Re: 51Packard's....51 Packard

Posted by Ross On 2010/8/18 21:20:25

You are right, the two big round things are the housings for the pistons that operate the low and reverse bands. The one sticking up in your photo is the low piston.

To further complicate matters,49-54 Ultras had two-stage pistons: the inner or "fast acting" piston was to get the band's attention, so to speak, and then the main piston would rise up and actually clamp the thing so the car would move. These fast acting pistons were included so an owner could rock the car in sand or snow without a lot of banging--Packard attention to detail. Anyway, only your fast acting piston is sticking up (sounds like a personal problem) and should retract if you push down on it long enough to let the fluid ooze out. If it won't, remove the whole piston from its housing and press the center "button" on the opposite side of the piston. The the fast acting piston will retract. While you are in there, be certain that the lip seals are somewhat pliable.

I usually use brake cleaner for cleaning valve bodies. Get yourself a big old sheet cake pan to work in and the little bits won't go walkabouts. Be painfully careful about the order pieces come out of the bores of the valve body. There are pieces in there that are not shown in the shop manual.

That said, I still maintain that your lack of low was caused by improper assembly/adjustment of the band struts. Also, if your high clutch had burned up already, there would be a lot of debris in the pan.