Packard Forum Index » Modification Discussion

I've been looking at the mechanical interlock system between the buttons, my initial thought is to modify the panel to make the six buttons independent and spring actuated, and use the contacts as momentary switches to send signals to the 4L80 actuator controller. It may still need a separate controller (maybe spare capacity in the Microsquirt TCU) to convert the switch signals for the actuator controller. My ideal would be to have P-R-N-D and use L & H as +/- manual gear selectors. Another option would be to have L and H activate different shift maps, or use them for some alternate function.

The Packard pushbutton assy is actually fairly complex with all the buttons interlinked with levers and blockers so two buttons cannot be pushed at once. The mechanisms are what holds the buttons in so not sure how easy or even successful you would be in removing all the mechanical interconnections and trying to add individual springs.

Depending on what type actuator you would use on the transmission another issue might be that the electrical output from the buttons is fairly "dirty" and if you are going to try and interface with any modern solid state actuators the signal may be too erratic for reliable operation. You might need to convert the mechanical contacts to some sort of solid state switching with a decent solid state compatible power supply. If you do succeed in making the buttons spring loaded individuals, then instead of solid state switching maybe removing the long duration slide type contacts and converting to fast snap action microswitches as Riki detailed in his blog could work instead. That might provide a clean enough signal the solid state didn't go crazy. You may still need to provide a rock solid clean power supply though.

It might be easier to try and adapt some sort of modern control assy into the existing pod. I don't know what all is out there in the way of shift units but here is one that works with a GM trans and looks to be fairly flexible.

If you wanted to keep a stock look possibly some method of attaching the existing plastic and chrome PB caps to the new controller could be found but not sure if the layout (on this brand) can be changed or if there is another brands control assy that would orient properly in the Packard pod.

I would imagine that as long as the switches work "properly", i.e. have clean and springy contacts, that the signal would be clean enough. If not, then the best solution might be to use some microswitches IF they would physically work well.

You could also make some delay circuits using a relatively simple array of capacitors, resistors, and transistors/SSR's but this is likely overkill.

Just having like a 1mF capacitor bridged across + and - between the button and actuator would help filter the signal and would probably be good enough. If you are having only minor problems, or no problems but you worry that you might later, this would probably be the best solution.

Warning: capacitors will burst if you hook them up with reversed polarity.