So, I pulled my posi apart since it's not doing anything. The cone is not bottoming out yet but it's worn, I have a feeling both the cone and housing are worn. Now, I could shim the spiders but then it would wear even deeper over time, ruining the housing. If I replace the cone, will it sit properly or just higher than the one in there now, so that over time it will wear too, the housing will wear even deeper and the mess is even bigger than now? This case had never been opened before I think, one side has a small shim, the other side had nothing. What I'm worried about is that if I shim it it'll bottom out pretty soon. In other words, what's worn here? just the cone or the housing too? I'm betting both. Maybe I can put the cones on a surface grinder, take some off the small end so it an sit deeper and shim up the rest.......

I'm no expert, but I've resurrected a couple. I file (yes file) a few thousands off the bottom of the cones and then shim out all the play. They have worked long enough for me to lose interest and move onto something else.

What do you file off? The outer ridge or the center or both? The outer ridge bottoms out behind the inspection window but the center will wear out on the ridge in the housing if it wears deep enough.

What a crappy design this is, sure it's a whole lot easier to put together than a dana, auburn or eaton style positraction unit but whoever came up with this system of 2 parts wearing each other down without a replaceable friction surface is nut.

I filed the bottom of the cones (outer ridge I guess). You're right that it won't work if the center hits (without milling it) but that wasn't a problem for me. BTW, I doubt that shim was there from the factory. I think someone's been in it before.

They are a poor design for many reasons, especially the guarantee of contaminated oil as they wear. Fairly strong though.

Yep. I too have torn a few apart. I have lathed cones and shimmed. They are garbage. Mine won't lock up around a turn. Works great at the track though, If I powerbrake they will lock, then I roll up to the line and it works great...

I think I am going to end up going to a ford 8.8 when i get out of school in a year.

Okay, so what exactly did you mill off the cone? Shims I have plenty from doing Danas and Eatons. From the looks of it, both the edge and the center need to be milled down. The outer edge will contact the housing, as visible from the sight window and the inner part will contact the housing on the ridge where the axle comes through.

I'm going to put a big neodymium magnet in the case to collect most of the shavings. I also have a feeling someone put limited slip additive in it, accelerating cone wear by allowing them to slip. this, because it deteriorated rapidly and it sure smelled like it had the additive, it has that terrible rotten eggs smell.

i'm going to stick with this rear, if it goes kaput I will throw a corvette IRS in there, I have all the parts for the swap, fabrication no problem.

No one knows how to machine the cones?

This is what I machined off. Just enough to get the surface flat again.

That's what I figured and described above, machine the outer edge to get clearance in the sight window and the inner part so it doesn't ride on the surface where the axle comes through. Assume equal amount on both removed so sight window indication is still accurate indication of clearance of the inner part w/ the case. I'm going to mill 2.5mm off mine and shim the damned things up.

These pics are off a spare unit I bought off the bay...I don't have it here, someone else took these pics for me. Looks like the cones are already bottoming out evident by the developing chamfer on the cone face. Any input here? Looks like this one is worse than the peg leg I took out.







This is my old one:

Here ya go. Beyond this swap for a Ford 9 inch or a Chrysler 9.25 inch out of a C Body. http://www.justdifferentials.com/ind...cfc07821bcc1ec