Projects 1947 Ford banjo open drive advise needed

Looking for some advise...any help will be greatly appreciated.
I bought this rear end for $100 and thinking of using it for my next project.
For what I have been told, it is a 47 open drive with 3:78 gears. There is a stamping on the bottom that reads "34". After some turning and counting it does appear to be correct for 3:78.
It does turn smooth with no play. The oil looks clean and no water in it.

I am planning on running a flathead and t5 transmission set up and using 17x750 tires on the rear.
These are the questions I have. What's the best way to connect the transmission to the rear end. My frame will be about 12" shorter than stock ...so I am assuming a custom driveshaft?? If so, any recommendations as to where can I get one?
Is the gearing on this rear end good for freeway driving or should I look for different gears, like 3:54?

Also, any way to tell the condition of this rear end without taking apart? How difficult are these to rebuild, if need?

Thank you for any help....really new to all this so any and all info is valuable.

 

Its a truck rear , notice the leaf spring pads.

 

Open drives that year are ALL truck rears. Great buy. Custom shaft for sure. And with a 5 speed you will be fine on the highway with that gearing.

 

Thank you for the replies. Yes, I am building a truck so thats a good thing. I figure it would be easier to set up

 

Hot Rod Works in Nampa Idaho is a good resource for these old Banjo's. I have the same rear end for my current hot rod build...my 29 Chevy 2 door sedan with a 283 and 3 speed OD.

 

I'm trying to figure how to get the yoke off one right now, its a tapered shaft with keyway just like a wheel hub on an axle. Why is everything more complicated than it ought to be? I thought I'd pull the pinion nut and the yoke would slide off a 6spline coupling, nope! Tapered shaft end with key staring at me in there. I wish I had left it alone but now I've loosend things and must have affected the seals.
Just so you know.

 

Truck + flathead + T5 + 3.78s + 17:7.50s is pretty tall gearing. I wouldn't look at going taller.

Is this a truck as in a pickup that will get used to haul the occasional load or a bobber truck that is for passenger transport only. The 12" shortened frame might suggest the latter. The gearing will be ok either way but the 3.54s would be too tall, especially if load carrying is expected.

 

MOST open drives I've built wer 4;11 GEARS.

 

I would spend some time attempting to clean up the bearing surfaces on the ends of the axle housings. They look really rusty and may be too pitted to serve as a bearing surface for the roller bearings that go inside the rear hubs. If they're bad the housings need to be machined down and sleeved to be useable, so you will be pulling the axle apart for that process. Also check the keyways closely if you think you will be using it without tearing it down.

 

I hate to tell you but... you probably should take the whole thing apart now while it's sitting there. There are hub bearings in there as well as a pinion bearing all with races that most likely are toast. You don't want to install it and just have to take it out later. And they are not the easiest thing to rebuild and no modern shop will do them anymore. Sooooo
Read up on rebuilding a banjo and have at it. Better to be safe than sorry at this stage of your build.

 

You are right, I don't want to install it to find out it needs to be rebuild.
Anyone knows of a "how to" link or any advise for a shop her in LA that can on the task?
I cleaned up all the rust off and it appears to be all in good shape...most of it was surface rust.

 

You're probably SOL for gear sets in that rear. To my knowledge, nobody makes the pinion for that rear. So, whatever it is, it is.

Other than the Pinion/Yoke, it's the same servicing/rebuilding/parts as any other Ford banjo Rear as far as I know. For $100 I'd say you got a good deal with those plates on it too.

You will need a drive shaft cut to the length you need and with the right joints. I found that an Aluminum Drive Shaft 1984 - 1996 Corvette 700R4 Automatic fit the bill when I was mocking one up. It's fairly short, but I forget if the joints were correct or not.

 

We had these open drive banjo rear axles here in Oz as well . All fitted to utes and all 4.11 gears as I understand it. The unit I have is fitted with 4.11 gears

 

As I understand it, most were 4:11 but there were trucks made with 3:78, though they were rare.

 

Probably guilty of stating the obvious, but it would be very easy to install that rear upside down. It has happened.. Just sayin'.

Mart.

 

I've had many of those rears with 3:78's

Clean those bearing surfaces with some emery cloth and I'm sure you'll be good to go.

That rear, tranny and tire combo will be awesome, there's nothing worse than doing 55 on the highway tacked out....you'll be crushing at 70mph


Oh yea, when that yoke finally "pops" off you'll know it! I think those are torqued on at like 250 ft lbs..

 

I have used a balance puller to remove the yokes in the past

 

I had on in my T that was 3.78. I converted it to car tubes with Buick brakes and F100 axle shafts

 

They also made that rear with a ratio lower than 4;11, I think it was something like 4.56, very rare, found in the 4 cylinder '42 pickups that had the 9N tractor engine. They only offered that engine two years, '41 and '42.

 

I'm thinking 4.42 or 4.47 can't clearly recall

 

There was a 4.55 ratio available in V8-60 powered commercial vehicles.

 

But the V8-60 engines never came in the pickups that would have an open driveline. Wrong years.