I understood what you said,

 

B7AZ-4209-M .. 9" Ring & Pinion Kit-3.70-1 ratio / Obsolete ~ No Ford dealer or obsolete parts vendor has any.

1957/83 F100 / 1975/86 F150 // 1965/67 E100 Super Van // 1966/86 Bronco // 1969/74 E200 // 1975/87 E100/150.

1957/80 misc FoMoCo Passenger Cars (1980: Granada/Monarch/Versailles only).

Mid-year 1969: FoMoCo changed the differential bearings from ball bearings to "Slim Line" tapered roller bearings.

 

Thanks Bill. I was going to check with obsolete possibilities. You answered my unasked question!

 

Perhaps with all of your parts counter experience you might understand that the 9" pumpkin/chunk/center section/hogs head/pig found in a passenger car will bolt right in to a light truck. Passenger cars had Equa-lok from about 1964-1968, after that, you could get Traction-lok.

So here's how anyone can put a 9" traction-lok into a 1956 F-100:

Step 1 - Find a 9" axle housing, axles, and brakes from a 1967-72 F-100.

Step 2 - Put a 9" center section (aka - pumpkin, hogs head, pig, chunk, etc) from any 9" ever made from 1957 until 1982 and bolt it right in. Just make sure your spline count matches your axles.

Step 3 - If you don't like your gears or differential, go find one you do and bolt that in. You can find them in junkyards, swap meets, classified ads, craigslist, eBay, internet forums, racing parts distributors, specialists like Currie or Moser and even Ford motorsports (or racing parts...whatever they call themselves these days). You can have just about any ratio from 2.50:1 to 6.00:1. You can get traction-lok, Detroit locker, ARB, torsen, and myriad other limited slip and locking differentials. You can even get spools and mini spools. It all bolts in to ANY 9" housing ever made.

So it's not impossible to have a 9" traction-lok in a 1956 F-100 just because it wasn't available from the factory...

Incidentally, when I put a 9" in my 1951 F1 panel truck almost 30 years ago, I didn't like the gears that were in it and I wanted a limited slip. So, I put the pumpkin out of my mustang in it with 3.89 gears, an N-case and...a traction-lok!

 

No ***** Sherlock! I've known this since 1963, but the fact remains that .. AS ORIGINAL .. no F100 with a 9" was available with Limited Slip until 1968.

Limited slip (Equa-Lok) introduced in 1959.

1959 thru today: If the AXLE code stamped on the Rating/Warranty Plate, printed on the Certification Label begins w/a letter: Limited Slip.

If the AXLE code begins w/a number: No Limited Slip.

 

Yes, but since it's a 1956 F-100, we're not talking original, are we? 1968 is largely irrelevant to the discussion at hand as is what was available from 1957 through 1968.

I really don't know why you can't seem to get your head around this, but more importantly, why you have to be so grumpy about it... :/

 

This is the OP question, He knows he has a 56 with a LATER MODEL 9" rear end. No one cares what year limited slip was FACTORY

 

Or the clutches are so worn they don't do anything

 

Even then, the springs are usually exerting enough force that the wheels will both turn same direction...different story when power is put to it.

 

Sherlock,
This is Sir Watson. I understand clearly what you are throwing down as I, myself have swapped pumpkins out on my 69 f100 from CARS anywhere from the 60's to the 80's.
At the present, I even have a 3 spd with overdrive (4 cage) manuel trans from an 86 f150 installed behind my FE. It was a perfect bolt up to the tranny.

I did LOL when numbersdummy posted the emoji,

 

Come on guys, Bill, the NumberDummy knows his end and some of us who have the grease under our nails know ours.

 

Agreed, I did not mean to be disrespectful.
"Sherlock" Sir Watson" and the " :-beatinghead " Made me laugh so hard i almost peed....
Numbersdummy is a wealth of information

 

Thanks Flat Ernie. Interesting . . . . . . The Difference Between EquaLok and TractionLok Rear Axles

I believe that EquaLok required putting a little bottle of the old whale oil friction modifier in the lube like the old Jeep QuadraTrac transfer cases. When the ban on whale hunting came into effect in the early 80s you couldn't get the good stuff so they came up with a synthetic friction modifier that was never as good as the natural whale oil.

We all need to understand what these differentials do before going to all the trouble to install them then being disappointed with the results.