This is a how to on reconditioning a cone style sure grip unit. This is not a boni-fide approved repair in any book or manual. I have done a LOT and I mean a LOT of them like this and never had a problem.
I am doing this unit for our member "73SwingerBuild". As you can see, it's a pretty clean unit out of the box. To disassemble it, simply remove the eight bolts on the ring gear flange. The preload springs will push the unit apart.
EDIT: This thread is purely a how to. I don't intend for it to be a discussion of the operation of the unit. We have more than one thread where we can argue about that. Please don't clutter the thread with discussion or arguments of operation. Thank yall for understanding.
Once apart, here is what you have. Two screw type cones that lock into each half of the differential case when power is applied. It is a very good design, but, not rebuildable by any approved method. But we are gonna fix all that up.
A side shot of the unit shows how it is assembled.
Sorry for the blurry pictures. I am tired and I was shaking. Here is one half of the differential case. You can plainly see where the action takes place here. The cone screws into the case and locks into position locking the axle to the case when power is applied.
Another shot with the flash. There's no mistaking what happens here. The cones seat hard in the case halves and lock the axles to the case causing the sure grip function.
Here are the sure grip cones. You can clearly see where they have bottomed into the case, rendering the sure grip function useless. Other than this wear, the unit is in very good condition. The shiny area on the outer edges in this picture will be where the machining takes place. Once this area is machined down, the cones will seat against the sides of the case again and restore the sure grip function. When I am done, it will likely drag the outside tire a little bit on tight turns until it breaks back in because it will be like new again.
Here is the unit exploded. As you can see, there are not that many pieces. It is not a complex unit. I like simple and simple is what the cone type sure grip is. When I get the shims and get the machining done, I will go over the reassembly.
I hope you have enjoyed this so far.
Here is the unit all cleaned up, blown off and sprayed down with PBlaster to keep it from flash rusting. The spider and side gears look great with minimal wear. I'll get the cones machined later today and the shims may even be here later today as well. We'll see. The old tapered axle in the background is used to line the cones and side gears up. It would be a double barrel bastard to line up once it's together.
Alright, here we go. To assemble, first, you need two 30 spline 8 3/4 axles. Clamp one in the vise, as shown and slide the small side of the case over it. Like this:
Oh yeah, I almost forgot. Here are our freshly machined cones, ready for installation.
After dumping a little 90 weight into the case half in the vise, take the cone and slide it over the axle splines and into the case half.
Next is our shim that helps restore preload and gear mesh. Don't forget to add a little 90 weight as you go.
Next, add the side gear, and a little 90 weight.
Next, assemble the thrust block, spider gears and spider gear washers, bottom spring plate and install the cross pin and it's retaining pin.
Now, install the preload springs and the upper spring plate. Don't forget to slob some 90 weight on each time you add a part.
Next comes the opposite side - side gear and shim. Don't forget the 90 weight!
Now comes the remaining cone.
Now lower the flange half of the case over the assembly.
Start two bolts across from each other. You're going to have to push the case halves together to start the bolts, because we've shimmed the unit back up to where it once was. Just get the two bolts started a few threads and leave them loose.
Take axle number two and install it in the top case half to align the side gear with the cone. Make SURE the axle goes through both the cone and the side gear. If it does not, it will be impossible to align them once the unit is torqued down. You will have to loosen it all back up.
Get all of the bolts torqued down and remove the axles. Here is the unit all reconditioned and ready to go.
I hope you have enjoyed this. I did. It was fun.