Do I have 59 Rear diff or something else?
 

I just noticed the rear diff on my truck doesn't seem to match any in the shop manual. Kind of a weird looking creature with sort of a hood over the pinion.

https://www.ford-trucks.com/forums/p...ctureid=133377

C0AW-4298-A .. Bumper-Driving Pinion Retainer / 1957/60 Ford/Thunderbird Passenger Cars. Pic says 1957/59, cuz it's from the 1949/59 car catalog.

I couldn't find this part number or a pic of it in the 1957/63 truck catalog, but it was revised so many times, it could have been dropped.

It's also possible that the carrier assy aka 'pumpkin' aka 'drop out center section' from one of these cars has been swapped into your 1959, usually performed to change the ratio.

The rear axle ID tag is located under one of the bolts (originally at 5 o'clock) that retains the carrier to the housing. But by now, many are missing.

Not that I would ever dare to add anything to what NumberDummy has said, but here is a link you might find interesting.

Ford nine inch differential cases +

I am sure though that the site does not have a great proof reader and "specifics", geru that this site has so reader beware!

Thanks you guys!! Now I'm not sure if it's a 9" or an 8" due to the shape of the pinion cover. Will have to do a more careful examination and figure it out.

I'm off to buy a ignition ballast resistor so I can get the wiring back to original condition. Someone bypassed it long ago.

What bolt circle wheels does your F100 have, the original 5.50" or are they from a car with a 4.50" bolt circle?

I'll betcha they're 5.50" cuz 8" (introduced in 1962 midsized cars), has a 4.50" bolt circle, installed in Falcon/Comet/Fairlane/Mustang V8's initially. Used thru 1980 in Granada/Monarch.

I just love that kind of talk.

I kind of thought it looked like an 8", but it's hard to tell here from across the country!

Im wondering seeing as how you may have a different rear center section than what came stock in your truck and your truck is a 4wd rig. Before you drive in 4low or 4hi you might want to check and make sure both front and rear gear ratio are the same. Just saying. :-huh

Napa had my resistor in stock. :) The wheels are 5 on 5.5 with if I remember correctly a 3.375" center hole. Can't wait for my kids karate lessons to end so I can run home and drive it.
Cheers

Now that you mention it, my uncle had a donor truck piled up in his back yard and I think he may have changed gears in the back but not the front. I won't be doing any off roading for awhile but thanks.

So far without actually reading numbers on the carrier it looks like a 9" housing with a
quote: "Standard 9 inch" C7AW-E carrier along with a D2AW-A pinion support with guard. Thanks again.

On a side note I got the ballast resistor in and it fired right up. All thats left to debug electrically is the heater and dome light. Took it for test ride #3 to see if I fixed the speedo cable and wala it works. The needle is bouncy as heck so it's useless for mph but the odometer is working. :)