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Discussion Starter · #1 ·
Hey guys I picked up a traction lock today for a ford 8 inch/28 spline. Got it from a chevy guy who's brother gave it to him a long time ago when he owned a salvage yard. Wasn't going to fit in his nova, so I picked it up for cheap. Even though it's old, it looks brand new (he didn't think it had ever been installed).

So here's what I'm curious about - the only casting numbers on it are: 23D8J and the numbers 049-2.

Anybody have any info on this or what it may have come from? I looked around the 'net for a while but I couldn't find much on 8 inch traction lock stuff (except that it's rare to find), and nothing using those casting codes. It uses the clutch set up.

I'm just curious what exactly I have here.
 

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How about a picture? We aren't very good with just words. :) Is it just the clutch pack?

28 splines with clutch discs sounds right for an original Mustang limited slip rear. I have one but I rebuilt it so long ago that digital cameras had not yet been invented so I have no pictures. :D They could have been in an 8" differential with any ratio, mine is a 2.80:1.
 

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Discussion Starter · #3 ·
Ok here's some pics. Didn't feel like messing with pics at 1am last night. I've got one of the unit, one of the gearing and clutch pack inside, and one of the casting codes I posted last night.
 

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That doesn't look much like what I remember nor what the '66 shop manual shows so I don't know what year it might be. The clutch plates on a '66 are sort of grafted onto the back side of the ring gear with none of that squarish-looking can shape. The pinion and side gears are also enclosed in a case with none of them visible without nearly a complete disassembly.
 

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Discussion Starter · #5 ·
Yeah after you mentioned that I just went today and looked in my '65 shop manual, and sure enough it's exactly how you described it.

So, does anybody have any idea what this is? It resembles the exact same idea as an aftermarket auburn unit.
 

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looks like an Eaton Posi to me, dont know if it will even fit in an 8" housing. go on eaton's site and plug that number in and see what comes up? good luck
 

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Discussion Starter · #7 ·
Ok, so I've pretty much come to the conclusion that this thing is an 8.8 in, 28 spline limited slip. I have no idea who's it is, but at least I know what it is.

NOW - changing topics slightly, same idea though so I don't want to start a new thread unless I need to. I'm here to learn about these 8 inch rears, and what the rest of this pile of stuff is that I have.

I have a chunk that I bought a while back purely for the gears in it, the rest of the stuff was a bonus. From researching all this 8 in stuff and readiing about the different rears in my shop manual, here's what I've concluded, and I apologize for not being able to get pics of this other stuff.

I have what I believe is a true locker. In a separate piece that came with the chunk, I have the differential piece that when you look through it, it is sleeved with a spline all the way through, and a differential pinion shaft driven through it perpendicular. To me, this says that when the axle's are inserted on both sides in this sleeve, that they are permanently locked together forever, and the pinion shaft holds everything in place. Do I have this correct as a locker?

Second question: I read about the open carriers (conventional differential) vs. the locking differentials (limited slip with the clutches) in my shop manual.

It appears that these are practically identical looking, with the exception of the clutches in the locking one. Looking at the gears and the differential installed in the chunk I have, it appears that it could be the locking differential based on it's shape. I can only see inside one small hole where I can see the four spider gears inside with the pinion shaft, but there is no way of seeing any clutches behind the gears without dismantling the whole thing to find out what it is.

So is there a way for me to figure out what is installed in the chunk without cracking the differential open, or is that my only way of knowing?

Lastly, say this turns out to be a locking diff. and I want to reuse it. The shop manual and lots of people on the 'net show this as a very straightforward breakdown and rebuild. Is this something I could tackle with a rebuild kit, or should I take the chunk to a professional? Keep in mind I've done everything else on my car so the only part I might get snagged on is setting the gear depth and the fine tuning.

Or would it be better to proceed with my original plan and just steal the gears out of this one that I wanted, and plunk down 500 bones on one of those aftermarket limited slip units? I just thought it would be nice to use what I already seem to have.

Sorry for the multi question novel.
 

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The '65/66 8" were what you see in your '65 shop manual. As I recall, you can't see the clutches when its all assembled and the two look much the same although they are not exactly the same. The only difference for disassembly is that you are supposed to put the limited slip one in a 1-ton press to keep the Belleville washers (stiff springs) inside compressed so it doesn't fly apart and strip the bolt threads when you get down to only having one thread left on each bolt. I may have used my vice since I didn't have a press back then, but I rebuilt mine without a press. (Been too long to remember what I did.) Also, if its worn enough there won't be any spring action to force a locker apart since the clutch plates will be worn too thin for any spring force to still exist. That may be how I got by without a press.

The differential case you describe could well be an open one. I am not sure those parts were any different. The splines can't go all the way through or you have no differential actioin; each side gear is splined but there is a small space between them. The factory limited slip (not actually locking) was with clutches outside the actual differential section so the spider and side gears were not involved.

I have two open version 8" disassembled on my workbench now since I am trying to build one good one from the remains.
 

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You need to read this page:

Differential Types

This IDs the conventional, limited-slip and also traction-lok rear ends. There is a lot of other good info if you search under the Info tab. The pictures you show are of some other type diff.
 

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Discussion Starter · #10 ·
Thanks ivy for the link. That really cleared things up for me being able to actually see what I was looking for rather than guessing. I'm going to declare the separate piece I have as a spare conventional open differential. This is based on the first pic/left diff. Noting the raised "V" (not really a V but you get the point) in the bottom left, that was dead on identical to what I have.

Same deal with the diff that's installed in the chunk. Same raised "V" when I rotated the gears around. Comparing the two diff's, I figured out whoever had it before me drilled that hole into the case of the diff that I was looking at the spider gears through. Then they welded the side spider to the bottom spider gear.

I seem to remember reading about this as a crude way of converting this to a locker, as the gears lodge and can't spin/let go.

What's the value of the open diff (the one on it's own, not the modified one), and maybe the 8.8 limited slip unit I pictured? I may sell some of my stuff to be able to trade up to an aftermarket limited slip for my 8.

Any thoughts on getting that unit and installing it myself? As I said, most stuff I read about show this as pretty straightforward install and I'm pretty handy.
 

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As far as value of what you have: I haven't a clue, I don't even know what mine is worth except that its not for sale.

If you've got the $$ and don't mind dirty hands, its not difficult to install any of these especially if you buy the center sections already assembled.

In yesterday's searching I finally found the Equa-Lok clutch disks for sale - at NPD. I hadn't thought to look there. I don't find them anywhere else. They are also a pricey $125/set but beats walking I suppose. :) In 1980 I bought a set at the Ford dealer for something less than $22.
 
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