BIG KEVIN: You win half the prize for the trip to the middle of Lake Erie. You ae right that an lsd was also introduced by Studebaker in 1956. How ever the lsd wasn't offered on any other Studebaker automobiles. It was introduced on thier half ton trucks for 1956.

How I know that for a fact is that I just purchased a book titled American Light-Duty Trucks 1896 to 2000. This is a very complete on nearly every light truck produced in the USA.. Another book to add to my reference library.


John F. Shireman

OK--sorry I'm a little late on this, you may have already found your problem and fixed it, but here goes anyway.
Lets start out by sorting out some terminology: when you say "short" do you mean "dead short to ground"--where 12V current is literally touching ground causing the 30amp (push button system)circuit breaker on the fender well to click on and off repeatedly, or does the system just not function, stuck in one gear?
When you say "hot" do you mean thermally hot, as in "hot to the touch" (the wire is actually getting hot) or are you using the term "hot" to indicate the presence of 12V current? (A common shop slang term, I use it a lot myself).
When you say that you have conductivity between all of the wires indicated on your post do you mean that with an ohmmeter you get 0 ohms between brown (brown is connected to the reverse gear finger) and the other indicated colors?
I'm going to assume that the unit is not shifting, no one speaks of their pushbutton system until it stops working!
The unit seems from you description to be stuck in neutral (not the worst gear to be stuck in, believe me). You have depressed the "reverse" key on the control panel (shift buttons on the steering column) this has sent 12V current to the reverse finger on the segment switch inside the actuator. The shorting bar of the contact segment is positioned such that the 12V current being applied to the reverse finger is also feeding back power to the white(high),blue(drive), and purple(low)fingers/wires. The switch contacts for all wires/gear functions are "open" (not connected to anything at the moment) at the control panel, by design, so that explains the conductivity you are seeing. One wire you did not mention is the pink wire, and this is where the trouble may be. The two outermost fingers on the segment switch are the leads that go to the motor control relay on the inner fender wall. The pink wire pulls in the relay for one direction of rotation, the orange/black wire the opposite direction. If you have power at the above listed wires and NOT pink, you could have a bent finger for the pink wire (the finger at the left side of the contact segment) OR: it could be fine and the coil for that side of the relay could be bad. Can you push "park" and get any action or is it just dead?
The worst case scenario on these is that one of the two outer fingers (pink on the left, orange/bk on the right) is bent. When this happens you ain't going nowhere. Power can't get from the key on the console to the relay coil to cause rotation.
If you need to see the fingers down on the actuator, disregard the "actuator removal" instructions in the shop manual. Do this:
you need:
A floor jack
Two good hefty jack stands
Normal mechanics tools, sockets, wrenches
A small scissor jack out of a little cheap car
Many varieties of right-angle screwdrivers


*raise the front end (or side if you prefer), put the car on the jack stands

* put the floor jack under the pan of the trans, protect with a scrap of plywood

*remove the rear trans support crossmember, supporting the trans as above

*insert the 'lil scissor jack between the frame and the tail stock of the trans on the pushbutton actuator side (driver's side) and push the trans (diagonally) away from the frame

You can't push the trans too far, there are "stops" sort of built in. This will give you enough room to get the cover off of the segment switch portion of the actuator and see what's up (this is where the trouble is most of the time)

DO NOT REMOVE THE MOTOR FROM THE ACTUATOR UNLESS YOU ABSOLUTELY HAVE TO. DON'T DO IT, DON'T TRY--98% OF THE TIME THE MOTOR IS FINE, IT'S RARELY WHERE THE TROUBLE IS.

When I service a P-B unit this way I replace the slotted screws on the segment switch bridge and the cover with Allen head cap screws. G__ forbid I have to go back in (I usually don't) The allens give you six positions to grab as opposed to two with the fillister head screw.
You may have a situation where the end of the reverse finger is touching the ground of the inner cover (inside the actuator) I have seen this, I have seen contact fingers glow red like a stove burner! this will distemper the contact finger and make it worthless. Follow the above procedure and get a look at what's going on inside the actuator.

I picked up the parts today. They turned out really well. A real close match to the parts that I had already Painted with POR15. . I will have some more done since these turn out. Was trying to save some money by painting them myself but this seems to be a better route since allot of my parts are bare metal right now. To cold for me to do any painting.

Not sure if it helps or not, but some of the Automotive "Firsts" List out there on the web credit Studebaker as having the first Production LSD, and that was in 1956.

I also found this for you Packard "Firsts" People, I know some of these have been debated too death, but just reporting what is listed on Answers.com as Production Automotive Firsts. They make the caveat that while some of these items may have appeared on racing models, or prototypes before, this lists contains only items on Production Models:

First V12 - 1916 Packard "Double-Six"
First carburetor air filter - 1915 Packard Twin Six
First power door locks - 1956 Packard
First steering wheel - 1899 Packard

Honorable Mentions:

First torque converter automatic - 1948 Buick Dynaflow
Honorable mention - 1949 Packard Ultramatic (torque converter automatic)

First air conditioning - 1938 Studebaker Commander
Honorable mention - 1939 Packard and 1941 Cadillac

That is all they list for Packard.

The complete list as it is on Answers.com is attached for everyone to debate.

Attach file:

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Quote:

Well Tom is right in the respect that Posi (LSD) became an option on the Corvettes. But that was in 1957

Most manufactures had different names for the LSD:

Chevy was called Posi-Trac, Pontiac was Safe-T-Track, MOPAR was Sure-Grip, Ford was Equal-Lock.

Brain, HMMMM..if Lake Erie is a clue maybe the vehicle we are looking for is the Jeep CJ3 made in Toledo, Ohio? I don't know when the first "Powrlok" was offered but I think it may have been in 1956 but possibly earlier.

Dave,

I was thinking of Stude also, but for two things.

First, having merged with Packard in '54 to form S-P, Studebaker would technically be the same "manufacturer" as Packard. Yet, even that point may be moot, as the earliet reference to the "Twin Traction" differential being used in a Studebaker that I could find was for a 1957 model - though that was technically built in calendar year 1956.

Hmm, wonder if this is another one of John's infamous trick questions. For all we know the car he's referring to might very well be in the middle of Lake Erie - resting at the bottom. LOL!

Anyone else have a good guess?

I'm going to say Studebaker but if I'm right don't bother with the Lake Erie trip as I've been there about 100 times!

Guess it shows my age and how up I am on this stuff. I am not much of a reader. I more a hands on type of guy.

TOM: Not even close on either guess



Jon F. Shireman