Any thoughts on why my sure-grip did this?

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imopar360

imopar360

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Car info: 72 duster-318,mopar purple cam 340 repo grind,headman headers,2.5 exhaust with x-pipe,street demon 625cfm carb,and edelbrock performer intake.904 trans stock

3rd member Info: 489 case 3.23 gears..


A friend sold me a a-body 8 3/4 for my 72 duster and gave me this 3rd member for free.But my question is it safe to drive it like this or should i replace the sure-grip unit? And also if there's cheaper alternatives to the sure-grip units?

Or will it just be cheaper just to buy another 3rd member because I really want 3.55 or higher gears? Thanks


 
OH HELL NO!
Look at that pin how it has eaten into the housing.
Never seen one that bad that wasn't in pieces.
 
No don't drive it! It could lock up at hi way speed and cause big trouble. The ring and pinion and housing might be fine just look for another cone sure grip.
 
I can see why the third member was free...I definitely would not be driving on that. I would think a used cone sure grip would drop right in and be on the cheaper side of doing things.

From what I can see, it looks like the shaft that the spider gears ride on started chewing its way through the sure-grip. I'd like to see some pictures of the innards if you decide to keep and you get it taken apart.
 
looked like mine after 3000 whole shots and donuts my pin came out got cut in 1/2 and oblonged the hole out and the shearpin took out everything ,looks like the ring gear got it too , check it good might save the ring and pinion , but the rest is smoked keep that 1 for parts for a minute some 1 might give you a break like I got on a new used 1
 
imopar360 said:
Car info: 72 duster-318,mopar purple cam 340 repo grind,headman headers,2.5 exhaust with x-pipe,street demon 625cfm carb,and edelbrock performer intake.904 trans stock

3rd member Info: 489 case 3.23 gears..


A friend sold me a a-body 8 3/4 for my 72 duster and gave me this 3rd member for free.But my question is it safe to drive it like this or should i replace the sure-grip unit? And also if there's cheaper alternatives to the sure-grip units?

Or will it just be cheaper just to buy another 3rd member because I really want 3.55 or higher gears? Thanks
Click to expand...

I have never seen a pin eat its way through a case that much without grenading. IMO I would keep the housing just a but a new SG with what ever gears you want. Your going to have to set up the new internals anyways so adding a set of gears on top of it is no big deal, just the cost of the gears. Also, If your gonna be spending the dough on a new locking unit, take a look at the Detroit True Trac.
 
try to get in touch with bridges under search he usually has parts or a whole unit I don't have his whole name but look under search rear ends untillyou see #s bridges .thats where I would start
 
looks like someone was stuck and was doing the reverse to forward procedure for a couple of hours. I have a complete unit . The pinion put some marks in it when the pinon nut came off. Other wise it is fine. Comes with the bearings and races. $150 shipped. Steve
 
wow-- this is the one I had & the internals were not good-- can't imagine that one ^ Lawrence
 

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I got one out of a 71 road runner that was wore the same way. I just figured it was abused
I gave it away. Got a Dana & never looked back.
 
That is what happens when the two small pinion gears seize to the shaft. It causes the shaft to turn in the case breaking the .250 dowel pin. what causes this starts by the cones bottoming out in the cases and therefore spins the pinion gears more than was intended by design. Yours is the worst case I've seen of damage to the case. It was ran hard long after the cones quit holding in the case. Those two small pinions are impossible to find. The shaft can be replaced with a shaft from an open rear, but the gears? Good luck finding them. I have several cases I could built SG's out of if I could source the small gears.
 
Wow! I've seen 2 of them that the pin tore up the case on but neither were anywhere as close to as bad as that one. Whoever drove the car/truck that unit was in had angels watching over them
 
thanks for the info guys.Im just going to sell the 3.23 r&p and invest in a new sg unit and 3.91 gears
 
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