8 3/4 Sure grip information

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SMCARNUT

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I built a tester to measure the breakaway torque for 8 3/4 rear end center sections. A buddy gave me the old axles out of a C body. I cannot find the exact breakaway torque I thought I had it written down somewhere. Any rear end guru's have the exact breakaway torque spec on clutch and cone style sure grip units?

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To my knowledge, the only "accurate" way to measure that would be to measure it at the pinion. Measuring at the axle is "going backwards" from how the sure grips are designed. Since they are torque sensing (clutch type more than cone type) they "ramp up" when torque is applied. So measuring at the axle does not include "that". Some will argue that the cone type does not ramp up and is not torque sensing, but it most certainly is to some extent. All you have to do is look at how it's designed. "I guess" you could get a ballpark idea of how good they are at the axle, but I don't see it getting very accurate.
 
I can do it both ways at the pinion and axle. I tried it both ways on this old cone style sure grip. It was 25-foot pounds when I tested it both ways. Google said 100-120 foot pounds but it did not say cone versus clutch. Dr Diff website says he tests them to make sure they are 100-120 before he ships but that is a clutch style surge grip. I just was hoping that someone may have had the exact spec's for both units.
 
I can do it both ways at the pinion and axle. I tried it both ways on this old cone style sure grip. It was 25-foot pounds when I tested it both ways. Google said 100-120 foot pounds but it did not say cone versus clutch. Dr Diff website says he tests them to make sure they are 100-120 before he ships but that is a clutch style surge grip. I just was hoping that someone may have had the exact spec's for both units.
Wow. That seems rather low. I've seen some specs show 800 foot pounds at the axle. That was like form some of the Moroso Brute Strength (clutch type) units. So 100-120 seems low and certainly 25. Does Dr Diff specify whether he tests at the axle or pinion? Regardless, I would certainly respect whatever he comes up with.
 
This is from DR Diff website I will try and call him tomorrow.


New, reproduction 8 3/4" clutch sure-grip ("powr-lok") includes upgraded EN353 cr-mo 1 piece 30 spline side gears and spider gears.

These are not the same units offered by others. Each unit is bench tested to ensure 100-120 ft lb breakaway torque.
 
This is from DR Diff website I will try and call him tomorrow.


New, reproduction 8 3/4" clutch sure-grip ("powr-lok") includes upgraded EN353 cr-mo 1 piece 30 spline side gears and spider gears.

These are not the same units offered by others. Each unit is bench tested to ensure 100-120 ft lb breakaway torque.
Ok, clearly he knows what's going, I would think.
 
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