Rear axle ratio Ford 1947 QUESTION!
 

Hi all!
I have the chance to buy an used Differential that is complete. It is a 1947 differential but my car is 1946.
The question is: Is there something different? I´d like to buy it as spare part.
But before that I want to be sure if it is correct one for my car.
I attach a picture of it. It is on sale as it is.

Thank for your advises.

Harylufa

Re: Rear axle ratio Ford 1947 QUESTION!
 

The rear axel assy's for 1942-48 are the same with the exception of possibly a different gear ratio. There should be a number stamped on the bottom rib of the banjo that you can compare to your rear axel. Keep in mind the ring and pinion could have been changed at sometime prior and is now different than what it came with. If the price is right it would be a good investment no matter what the ratio is.

Re: Rear axle ratio Ford 1947 QUESTION!
 

What he said.

Re: Rear axle ratio Ford 1947 QUESTION!
 

Funny you should ask this question. Just a couple of hours ago I stumbled onto this discussion by "Uncle" Tom McCahill* about the difference in gear ratios in the differentials of the '46 and '47 Fords. Very interesting read and very enlightening: http://auto.howstuffworks.com/1941-1...er-deluxe8.htm

Wish I had that '47 rear axle right now. Looks like I'm probably going to need it or at least parts from it. (https://www.fordbarn.com/forum/showthread.php?t=89703)

*Uncle Tom McCahill conducted the first published road test in America which appeared in the February 1946 issue of Mechanix Illustrated. The first car he road tested was a 1946 Ford DeLuxe sedan - just like yours Harylufa (except yours is a coupe). (More about "Uncle" Tom here: http://www.joesherlock.com/Tom-McCahill.html)

Re: Rear axle ratio Ford 1947 QUESTION!
 

Henry, save that link to McCahills review of the gear change. Whenever someone asks about ratios on the Barn, post that link. McCahill was a very well respected expert on cars, as can be attested to by the review. I used to love reading of his road tests, as did most kids I knew back then. Tom was very influential back in the day!

Re: Rear axle ratio Ford 1947 QUESTION!
 

Hi all!
I was trying to find out "There should be a number stamped on the bottom rib of the banjo that you can compare to your rear axle" told by Gary in LA but it is impossible see it.
What do you think If I buy this differential? the price U$s 120.-COMPLETE as you see in picture including rear spring assembly too.

I think it is a real opportunity.

Please help me to decide

Harylufa

Re: Rear axle ratio Ford 1947 QUESTION!
 

Just buy it, for that price it's worth it just for spares.

I put a little video on youtube showing how you can check the axle ratio.

http://youtu.be/bkvp3Fq21ZM

Mart.

Re: Rear axle ratio Ford 1947 QUESTION!
 

Hi Mart!

I have just seen the video It is very interesting, thank you for showing us how to check it.

Please if you have something more that i must know please let me know.

Harylufa

Re: Rear axle ratio Ford 1947 QUESTION!
 

Hi All!
Finally I bought the diferential. I attach some pics.
Please I´d like you take a look at this and please!!! give all your opinions.
I want to take this as a PROJECT and rebuild it if I can. All information you have tutorial pics etc etc, will be welcome.
I hope did a good purchase...
Keep in touch

Thans all

Hary

Re: Rear axle ratio Ford 1947 QUESTION!
 

$120. Looks like you made out pretty well. You'd be lucky to get the spring for that over here.

Re: Rear axle ratio Ford 1947 QUESTION!
 

Hi!
Yes, I must clean It. How can I know if spring are in good conditions?

Thank you.

Hary

Re: Rear axle ratio Ford 1947 QUESTION!
 

Regarding the pictures... Turn it over, bottom side up. Clean off the web that is directly below the pinion bearing - should be some numbers stamped there, numbers like 39 11 or 34 9 or 37 9.
The brake assemblies, at least in my area, are worth most of what you paid.
As for condition - a look inside would be my next interest. Most of the rear ends that I have pulled apart, if they have been stored outdoors, have had water in them. And, there is usually nothing usable in them. You could pull the fill and drain plugs first, and see what you can see. Water or rust would be a bad sign. Looking through the plug holes with a flashlight (preferably at night) might give a clue as to what the inside looks like.
As for differences... 46 and 47 were years that some changes were happening, at least at US plants. Nothing that would make any difference to you, but sometime along in there, they introduced the brackets (bolt-on) that were to later be used for tube shocks - on some 47's, and 48's. So, it's possible that your 46 would likely not have some unused lower shock brackets. And, the 47 might have some lower shock brackets installed. No big deal, and it would make no difference.

Re: Rear axle ratio Ford 1947 QUESTION!
 

Check for broken leaves first. But as far as being worn out (needing to be re-arched) I'm not sure other than putting it in and seeing where it sits, maybe someone on here has a better way to tell.

Re: Rear axle ratio Ford 1947 QUESTION!
 

Hi BOBH!

I will investigate all you mentions and came back with news

Thanks

Hary

Re: Rear axle ratio Ford 1947 QUESTION!
 

Fibber Mcgee!!

One thing that I have to do is change front springs and back springs. My car jump always and its very hard.

I must find out if this one work fine, in this case I ´d change it.

Keep in touch and thanks

Hary

Re: Rear axle ratio Ford 1947 QUESTION!
 

Make sure the bearing surfaces under the tape is in good shape. As long as it wasn't stored out side with the torque tube bell up and not covered it shouldn't have water in it. G.M.

Re: Rear axle ratio Ford 1947 QUESTION!
 

Somebody mentioned the brakes... Those brake shoes are unobtainable here in the States, do your best to salvage them.

You have a 19 tooth speedometer gear, which indicates a 9/34 pinion/ring set, producing a 3.78 final ratio. This is a good all around ratio for your car, likely the same as you have now, but will be a spare.

What Are You Likely Going To Need?
 

The 3.78 ratio is OK but if you ever need to use the gears, it would be better for many well funded owners to buy the 3.54s and give your engine and ears a break at road speeds. Next thing would be the axle bells. Ford discontinued the grease fitting at the cost of more worn housings. If worn, they would only be a convenience to sleeve the bearing race on the spare before taking the car out of service. Condition of the axles in case your originals are either stripped or spun on the taper is usefull. Brake parts can be useful if included. Springs may not be that thrilling unless yours are rusty. Super Deluxe had the desirable covered spring. Others, not so much. Inspection of what you have will give a better idea how useful a spare may be. Good Luck: Fred A

Re: Rear axle ratio Ford 1947 QUESTION!
 

Hi all!
Here I found a number. What do you think? Now I must discover my number diferential.

Please keep in touch

Thanks

Harylufa

Re: Rear axle ratio Ford 1947 QUESTION!
 

Hi!
I think you are right;
"which indicates a 9/34 pinion/ring set, producing a 3.78 final ratio."

Now is this correct?

Harylufa