Any differential guys here?

[jimynick]

Note that I didn't ask for rear end guys! LOL Seriously though, my 74 Challenger has developed a "crunching?" sound in it after being driven some. I suspect it's the SureGrip as mine's a cone and the noise sounds consistent with a inner cone binding/slipping inside the outer cone. It had new fluid installed and a bottle of the Mopar SureGrip juice as well. Does anybody have a cure in mind? If I can fix it with a further fluid change and additive I'd be a very happy camper, but I'm out to learn here and all and any suggestions will be gratefully received! 

[Filthy Filbert]

Well, since I am not a differential OR a rear end guy, I would suggest contacting Cass our in Montana, aka "Dr Diff" as he may be able to lend some advise on how to save it from needing a total rebuild

[anlauto]

So, you want to fix your crunching noise in your rear end with more lube ?   I'm staying away from this one

[RUNCHARGER]

I'd probably drain it and see what the fluid looks like. If there's no metal in the fluid I would try different fluid and maybe the Ford limited slip additive. If it isn't mechanical then it doesn't like the new lube package that was put in. If it was doing this before you changed lube then a component is probably leaving the building. Those cone sure grips aren't that great anyway.

[Brads70]

My local parts supplier buddy always gets me the ford LS additive as he says it works well. He's an old circle track racer and his knowledge has always helped.
Just don't get any of that additive on your hand or you will be smelling it for a week.....

[blown motor]

So, you want to fix your crunching noise in your rear end with more lube ?   I'm staying away from this one

[jimynick]

So, you want to fix your crunching noise in your rear end with more lube ?   I'm staying away from this one

What are you two old sodomites laughing about?!   I think I'll try the change the fluids and see routine first. Thanks for the replies!

[Chryco Psycho]

The cones wear away the gear mesh  becomes loose leading to play between the spider gears & axle gears ,crunching noises means the spider gears or axles gears are broken , I have destroyed 5 center sections in a similar way although mine were not worn when I busted teeth off .
Pull it apart now .
My best achievement was tearing 10 teeth off the pinion & 37 teeth off the ring gear in less than 1 tire rotation .

[jimynick]

Thanks Neil. I was hoping for better news, but I agree that it's got to come out for at least a looky-see.   

[Chryco Psycho]

Bad news sucks but you have to do what you have to do .