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

mystery switch;
a vertical cylindrical switch which points downward and is actuated by a piece of the accelerator linkage ,it hangs off the firewall just inner side of the steering colomb
is this a kick down switch ?
the ultramatic will only kick down and go into low gear going up a hill if I pull my foot off of the accelerator,like a fluid drive ,is it supposed to? is that have to do with a nonfunctioning mystery switch?
is thers a vacumb system for the downshift ? I recall when changing out the fuel pump there was a vacumb line going back to the transmission which shared a "t" witht he vacumb line to the wiper motor

The mystery noise ;
only when going up a steep hill ,a mettalic rattly noise like some rocks in a coffee can or something rattling loose against something ,it does not sound rotational ,is random sounding ,i cant make it change by letting of the accellerator to slow the sound down,doeas not happen at any other attitude ,ie flat or down hill .the ultramatic has about 70,000 on it and has had a recant fluid change which didnt change anyting I had noticed some surge but I thaought that was too much strain on the engine going up the hill at a too low rpm
I have replaced the exhaust with kanter pre done pipes and muffler and it rattles agains the frame in a couple of spots, but I usually hear this only when the engine is cold and starting up ,so I dont think thats it ,am I looking at a trans rebuild?

There is no vacuum connection on an Ultra. Kickdown is strictly controlled by the throttle rod adjustments so no switches either except for the neutral safety start switch operated by the selector shaft detent cam. It should drop out of direct drive below about ll mph or if below about 50 or so, when throttle pushed quickly open. Normally the vacuum section of fuel pump is in series between carb or intake manifold vacuum source and wiper. The extra vacuum connection could be for a windshield washer or a rear window wiper if you have (had) one. Anything else would be an aftermarket something. It is also possible the fuel pump vacuum is not plumbed properly if there is a tee but no accessories.

If you had an overdrive instead, the kickdown switch would be rectangular with 4 terminals. I suspect the item you mention is a spring loaded air check like device which slows the closing & prevents the accelerator from slamming shut and stalling the engine--sort of like the dashpot mounted at the carb on some of the earlier cars. IIRC it was a round cylinder about 1" diameter and a couple inches high with a plunger an inch or so long out one end.

The "rattle" is most probably pre-ignition from the timing being a bit too advanced. Best to check the ignition timing with a timing light, but as an alternative, remove the distributor cap and have someone hit the starter for a second to see which the rotor rotates. Put the cap back on, loosen the distributor hold-down clamp, and rotate the distributor in the same direction a SMALL amount, a couple of degrees (may be 1/16 inch at the distributor body perimeter), and then take another test drive. If the noise has lessened, do a proper ignition timing.

heya wow ,that would make sence since the "switch " wasnt connected to anything ,Ill paly with the linkage and see how it funtions ,Ive had a couple of old cars that had something like that on the side of the carb and i never knew what they were for untill just now ,thanks ! I got a timing light and tried to see if I was 6 dbtdc as is speck but couldnt see any timing marks ,the dwell was about 30 degrees ,Im going monday to have a valve adjustment and will discuss the mystery noise as possible valve clatter or now preignition with them is preignition the same as "detonation"?
Happy Holidays !thank you!

ps
if flooring the accelerator isnt enough to shift the ultramatic ,should I adjust the throttle linkage ? Theres a couple of places where I could " tighten" it by adjusting a double threaded piece the service bullitin had a fairly complicated sounding adjustment proceedure

It would be good to verify the adjustments but if you work with throttle linkage, remember that is the single most important adjustment so do it by the book. If you mess it up, it affects all the internal pressures and if too far out of spec and resulting pressures are too low, can lead to burned clutches in short order.

Make all the preliminary checks and set the distances by measurement and visually in the order they tell you. SC 27#2https://www.packardinfo.com/xoops/html/downloads/SC/SC-VOL27NO2.pdf has the procedure as well as SM.

Since you don't have the special tool, use a scale and set the dimension for the preliminary upper rod adjustment at 2 3/4 inches from center of rod to top of head. That will duplicate the measurement in the latest revision tool and you don't need to account for the shims they mention in the procedure.

Attach file:

---

  (67.07 KB)

thanks Ill try the 2 3/4 inches first that seems easy enough ,If I had a 52 200 what series would tht be ?would that determine the cu inches of the 8cylinder engine?
I wonder if those two tools are available for the cross shaft to throttle and throttle to carb .there were three tools possible for the carb rod in the service bullitin
,Ill leave the transmission link ajustment to the guy that rebuilds the transmission some day,Ill print out the bulitin it sounds mysterious ,because of the spring compression

If you have a 52 or 25th series it should be the 2501 chassis so the only throttle tool you would have needed is the one shown. The others were for the 50 trans which has a totally different throttle rod setup.

To see what engine you have, check the motor number against the listhttps://www.packardinfo.com/xoops/html/downloads/PackardEngineSerials.pdf It should be a 288 but possibly there was an optional engine installed

I think the switch on the steering column which is attached to the shift linkage is the neutral safety or backup switch depending on the year and application.

thanks!
good to know about only the one tool that I need for my year could be "faked" by a simple measurement .very helpfull esoterica!

It said in the service bullitin that the spring loaded throttle stopper which is the" Mystery switch " sould b e eliminated for the 24th and 25 series if I read it right and the downshift accheived by flooring the accelerator ,
I have to do a "pull off" of the accelerator on a hill to get the downshift under a heavy uphill load ,it seems to do it itself if its not loaded to hard .

.Ill check to see if the vacumb line back tword the rear of the car where it "t",s off the wiper motor vacumb line goes nowhere ,perhaps there was a rear wiper at some point in the cars life thats not there any more ,may be a big vacumb leak that could be eliminated !

With my newly aquired $11.00 ebay 6-12 v antique timing light I didnt see timing marks on the pully ,just the pointer thing ,does one estimate the 6 degrees before top dead center to check the timing?I'll to see if I can get rid of the detonation knock or at least eliminate this .I wonder if the 1 gallon of diesal/tank trick I hear about would help this