1966 9" Rear Diff Questions

[bulletpruf]

Fellas -

I picked up a '66 frame, engine/trans, and suspension recently. Sold the engine and trans, kept Dana 20, Dana 30, and 9" and selling the frame.

Disassembled the 9" yesterday to see what I have. It's a small bearing diff with 28 spline axles, has 4.11 gears, and certainly appears to be original to the frame -- case and pinion support are dated October (J) of 1965, same month the Bronco was produced, based on the VIN.

Anyway, I had planned to keep it as a spare for one of my Broncos or for the next time I pick up a Fairlane that has an 8" rear.

Questions -- do folks restoring '66's care about date coded stuff? I wouldn't want to part this out or modify it if someone out there is in need of it for a restoration.

Also, is this a locker?

Thanks,

Scott

 

[DirtDonk]

For the general Bronco population up to now? Nope, nobody cares about the finer details. Well, I should not say "nobody" but it's certainly a low percentage and it does not usually enhance the value of the truck except for those few that are really keeping things original.
More often than not the upgraded heavy duty and more modern stuff sells better than old, just like new paint gets more than old patina.

But there are a growing number of folks that are doing that. It's a natural flow of course, from the last few years of Broncos becoming a commodity and collectible rather than just a cool old truck.
So up to you. Put it out there and see who's interested. You don't have the original truck so it no longer has that built in value for you personally, but for someone doing a full resto that no longer has their original rear diff, it could be gold.

The problem there is that most EB's still have their original 9" setups. I'm sure more and more of the "Broncos-in-a-Box" that people are picking up are missing more and more of the cool stuff though. So it might come up any time.

Paul

 

[DirtDonk]

Sorry, can't tell you if it's a locker or not. Are there any open inspection holes in it's side? Like two of them where you can see the side gears?

Paul

 

[bulletpruf]

For the general Bronco population up to now? Nope, nobody cares about the finer details. Well, I should not say "nobody" but it's certainly a low percentage and it does not usually enhance the value of the truck except for those few that are really keeping things original.
More often than not the upgraded heavy duty and more modern stuff sells better than old, just like new paint gets more than old patina.

But there are a growing number of folks that are doing that. It's a natural flow of course, from the last few years of Broncos becoming a commodity and collectible rather than just a cool old truck.
So up to you. Put it out there and see who's interested. You don't have the original truck so it no longer has that built in value for you personally, but for someone doing a full resto that no longer has their original rear diff, it could be gold.

The problem there is that most EB's still have their original 9" setups. I'm sure more and more of the "Broncos-in-a-Box" that people are picking up are missing more and more of the cool stuff though. So it might come up any time.

Paul

Thanks for the details, Paul. I'll put out the word in the local Bronco community just in case anyone is looking for date coded stuff.

No inspection holes in the side of the differential. I'll figure it out.

Scott

 

[72_EB]

Looks like an open carrier. No locker (or limited slip which would be the factory option).
'66 had no fill plug in the third member center section. The fill plug was on the 9" axle housing pumpkin that year. So the third member carrier could be worth something to someone wanting to keep it '66 correct with no filler. Like you said, that pinion support would be and is correct for '66.

 

[Viperwolf1]

It is an open diff.

 

[Broncobowsher]

The 1% doing a full original rebuild might care. The rest won't.

Most can't even use that center section since it is missing the oil fill hole of the later axles. So it is really religated to the '66 housing. It's not a performance piece. And even though it only works on a '66 housing, nobody with a '66 is locked into that third member. Any newer third member will work in a '66 and you just have an extra fill hole. So it is actually one of the least desirable third members out there for the 9". So to find someone who really wants it, you have to find someone really after a date code correct '66 and nothing else. And someone who actually wants one that doesn't already have one. You are probably down to an audience of 3 people? 2 of them are only looking if it is cheap and the third already has a line on one.

But as soon as you get rid of it someone will come looking for it.

 

[ared77]

"But as soon as you get rid of it someone will come looking for it."

Ain't that the truth! ;D Happens to me every time.%)

 

[WILDHORSES]

If you are keeping it for a spare or whatever drill and tap an NPT fill hole in it.

I don't like that case mainly because I installed one without realizing there was no fill hole in it. So that was a job we had to do over. Also the small bearings.

You might throw it in classifieds for a week or two. 4.11, that's desirable to a lot of people.


Jim

 

[bulletpruf]

Thanks for all the input. I'll keep the housing as a spare and keep the gears as well. I don't have any 4.11's, but have a 9" in my Fairlane, my Javelin, my Broncos, and plan to install one in my GTO. In other words, the gears will come in handy.

On a related note, I'm thinking the 28 spline axles are pretty much worthless, right? I guess I'll keep them as spares, but all my stuff is 31 spline except for the '69 Bronco and the '68 that I'm working on for my brother in law, and I'm going to update that to 31 spline as soon as I can.

Scott

 

[thegreatjustino]

I don't like that case mainly because I installed one without realizing there was no fill hole in it.

Remove the breather bolt in the housing and fill the differential through the hole. Replace breather bolt when done.

 

[bulletpruf]

There are a few C4AW cases on eBay now for around $150-$200. Threw mine up there, too. We'll see what happens.

 

[DirtDonk]

On a related note, I'm thinking the 28 spline axles are pretty much worthless, right?

Not completely.
As you noted they can still be used as spares for the vehicles you still use 28's in, but they can also be sold for a modest amount to someone that needs them.
Not everyone updates to 31 when one of their old ones wears out or is broken. Or even lost!

Some will find the seal surface too worn and don't want to do a sleeve and don't want to upgrade their whole setup to 31. Others may just be doing a religious restoration and want stock stuff.

So while not in high demand, there is still a market for them.
And if the bearings are still at least halfway good, they can be used as temporary drivers while the cool stuff gets collected.

Paul

 

[bulletpruf]

Thanks, Paul. I'll keep some as spares.

Scott