Hi. I'm a new member, and I'm pleased to have found this forum! I'm going to be putting my '47 1/2 ton back on the road, with your help. I have uploaded a few pics into my gallery, but don't yet know how to provide a link to them...

The biggest issue is that the rear end is frozen - differential fluid has leaked onto the brake shoes, and they've swollen tight to the drums (as a result of my own repair done many years ago...). Anyway, I've been thinking of switching it out to a more roadworthy rearend. Searching this forum, I found reference to bolt-in 67-72 Ford pickup rearends. I think I've located a '72 in a friend's back yard. My first question is, how do I identify the correct rearend, if I'm after one of these bolt-in replacements? My friend isn't sure if the truck is a 3/4 or 1/2 ton. Will that make a difference? Thanks in advance,
John

 

Half ton has five lug wheels. Three quarter ton has eight lug wheels.

 

It's actually 57-72. The front half of the differential unbolts to remove the carrier section. No pan on the back. It will measure 61 1/4" drum face to drum face or 57" axle housing stub to stub if the backing plates are gone.

 

Thanks mtflat:
The '72 I'm looking at was driven to where it sits in the field, so the whole thing should be complete. Sounds like I'll need some sort of adapter for the drive shaft?
John

 

So I just went to see the '72 and it is an F250, so I guess that means 3/4 ton and 6 bolt wheels. Rats. What does it take to convert to 5 bolt? Or is that a dumb idea?
John

 

There are no dumb questions, if you want to learn something.

Best to keep searching for the 1/2 ton rear end, they should not be that difficult to find, there were a lot 67 thru 72's made, so......just try to get a complete rear end, it will make life a lot easier, even if it needs re-built this is not a problem as everything is availabvle.

As far as an "adapter", it will depend on the yoke and your drive shaft, in my case I was able to pick up a universal at the local parts store with the two different end caps, other than that it was a bolt in. I did buy the later (67/72) shock brackaets to go on the frame so that I could use the newwe shocks.

Dave

 

If you can get the center chunk cheap and it's the ratio you want I'd consider buying it anyway. Then when you find a 5 bolt housing that chunk will fit it.

Vern

 

Thanks Vern.
I was wondering about that. The price is right - free. Sort of... I have to dispose of the truck, and I can have the rearend "free". I'm really not too picky about the ratio - just want something geared a little better than the original, which is what I have now.
John

 

Depending on what engine/transmission combo you are running you will want a ratio of around 3:00 to 3:50...

Vern

 

Try to make sure that the engine in the truck that is the donator is a V8. These are the 9 inch rears, and have the same 5 1/2 on 5 bolt pattern, as your 47 had orginally. The same wheels if you are looking for choice fit from 1940-1995, cars/trucks.

A friend of mine runs a 239 Flathead all stock with a 3.25 ratio, and he claims the truck runs great, and does a good job through hills etc. The hills I'm speaking of are through the PA, TN, Appalachan, hope I spelled it right.

Also the choice is very wide-spread as far as different ratios go. As an idea 2.75-4.?, and are virtually indestrcutible. So the choice is great and these are plentyfull. Best of luck to you and Merry Christmas.

 

Thanks for all the good advice. I'll take another look at the one I have access to. How do I determine its ratio?
John

 

Is that center chunk of the F250 the same as a 9" rear? If it isn't then you are limited to only the F250 rear. I always thought the F250 used a different rear.

 

Gary is correct; nothing from a 3/4 ton will interchange in the 9" 1/2 ton.
Avoid the f-250 model; they are too heavy and wide for your early applic.
Go w/ a 67-72 9" 1/2 ton w/ gears mentioned previously, especially behind
an auto. trans.; great for cruising at highway speeds, plenty beefy, and the
bolt pattern will match your early p-up front wheels/hubs. If using wider rims
and tires, you may have to narrow the left side axle housing to center the
diff. and keep the tires inside the fenders. I had to narrow mine 4-5/16" to
keep my slightly wider tires inside my '36 coupe. Another option is the earlier
57-59 pass. car 9" which are slightly more narrow than the p-ups, but also
have a smaller, non-matching bolt pattern. Use an open drive-line, not the
old torque tube assy.

Have fun with your project.....
Robb

P.S. re gear ratios; Some rear-ends will still have the tag attached on the
front (bolt side) of the diff. Most 60's - 70"s models will stipulate the actual
ratio, rather than a code.

 

Just for the record, on the 5 1/2 on 5 inch bolt pattern. The cars are the same from 40-48, then the trucks are the same up to 95. The hub caps will fit the 1940-48 cars/truck, then the truck from 48-56.

this is if you want to use your original hub caps.

 

I just picked up a '72 F100 9" for my '46 truck. There was no tag for the ratio so I turned the axle. Turns out it is 3.0. I would like to keep the flathead and original 3 speed in the truck. Does anyone have enough experince to know if this is too close for the flathead?