How To Recondition a Sure Grip Cone

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I Purchased an A bodied 8 3/4 741 differential that looks like it was separated from the car and sat in a backyard for years. Taking it apart carefully trying to preserve all bolts and nuts I noticed the pinion matched the pinion of 742 case and then looked at the numbers on the ring gear and shows 2800270 with research says it belongs to a 742 case. I'm learning as I go about this unit and visually can tell upon disassembly this is a cone style. I noticed the inside cone gear appears to be beat up on the side that sits in the cone. Question does the gear and the inside of the cone have to be machined as well. I try to rebuild by myself as much as I can...Thanks..Sean
 
A picture would be helpful here.
 
I have done this exact repair about 20 years ago. I was able to chuck the cones up in my break lathe and shave about. 060 off of them. I reinstalled them and they worked great. I was told this trick by my friends dad who was an old Chrysler line mechanic from the 70s and who also campaigned and worked on several mopar bracket cars. Great thread.
 
RustyRatRod said:
A picture would be helpful here.
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Here is the inside of the cones..I will bet the previous owner got them hot.

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Seansmopar said:
741 case with a 742 pinion...I hope I can salvage something with this case..it all turned before I took it apart..and it was no bind or slop..
Sean
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I wouldn't worry with any of that. You MIGHT go over them with some wet or dry and some mineral spirits but it's not necessary at all.
 
Thank you for an education! I've always wanted to rebuild a center section, now I feel more confident doing so! Thanks Rusty:)
 
This took some time to take all these pictures and share this info. And for no other reason than to help fabo members. Thanks Rusty very good information for all. Steve
 
Thanks Rob! You just gave me a great idea with what to do with the old axle stubs from the Dana I converted. Alignment tools! Also maybe make it a fixture for the lathe to hold the cones for turning them off. Might keep one for the D-200....
 
It's not a great pic, but I made these T-bars a lot of years ago. Also use them whenever I find a Sure Grip at a swap meet to check a SG for resistance.




 
The only thing different we use to do was to add 727 clutch springs inside the four pre load springs, a little tough on the street on corners but it kepted both wheels locked together at the drag strip.
 
Where does one find spider gears for these units? I have one that needs a set and another that needsgears and shaft. Thanks for the writeup!
 
mean318 said:
Where does one find spider gears for these units? I have one that needs a set and another that needsgears and shaft. Thanks for the writeup!
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you can use the cross pin out of an 8-34 open differential -- the spider gears are not available anywhere -- you have to salvage them , if possible , out of another trashed sure grip
 
@RustyRatRod I took my cone type sure grip apart today. 2 of the springs are broken, do you happen to know where I could find replacement ones? Thanks!
 
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