Difference between a Sure Grip and a Dana Power-Lok

[Cranky]

My 64 Savoy with a stock 74 440 auto big tires shucked all the ring gear teeth (42 case) in 20 runs, spool and 35 spline axels

Dang. Who set up the gears?? Do you know what the back lash was?

 

[Ceedawg]

Dang. Who set up the gears?? Do you know what the back lash was?

There when I bought the car, did have a Max Wedge but the previous owner bought it for engine then stuck the 440 in it. After rear broke in went the Dana and still there to this day, that was 1992. There’s ways I would build the 8-3/4 that I think would make it stronger. One is heating up the gears to 450 for 5 hours then cool slowly. 95% of gears are street gears and HARD-BRITTLE. Heating make them a tad softer, an old guy told me this in the 1970s, nascar thing he said.

 

[Cranky]

There when I bought the car, did have a Max Wedge but the previous owner bought it for engine then stuck the 440 in it. After rear broke in went the Dana and still there to this day, that was 1992. There’s ways I would build the 8-3/4 that I think would make it stronger. One is heating up the gears to 450 for 5 hours then cool slowly. 95% of gears are street gears and HARD-BRITTLE. Heating make them a tad softer, an old guy told me this in the 1970s, nascar thing he said.

Used to be able to get the "pro" gears for the 8 3/4 but as the 9" became the chosen one everybody (aftermarket) gave up on the 8 3/4. Setting them up with a little bit tighter backlash seemed to help a little....and using just a little bit of clutch to help preload the drivetrain did too but going to the Dana was the best thing we did for all the parts concerned.

 

[old guys rule]

The term "Sure Grip" is a brand name that the Chrysler Corporation used to describe their limited slip differential. General Motors had brand names for theirs, Ford and AMC did too.
You could have a clutch or cone type and the term Sure Grip would still apply.
My experience.....Many called the 8 3/4" cone type limited slip the "Auburn" unit since they were known for producing those. The Dana Power Lock uses replaceable clutch discs to facilitate the limited slip action and is often preferred since it is rebuildable.

Aren't sure grip clutches replaceable also?

 

[Cranky]

Now I have to make a weak point in the drive train thinking front u joint whats your thoughts? Remember I do stupid strong.

Use the better U-joints and don't use stock axles.....

 

[old guys rule]

Use the better U-joints and don't use stock axles.....

Aren't sure grip clutches replaceable?

 

[Cranky]

Aren't sure grip clutches replaceable?

Yup but the cone unit can be machined to work again if the guts are not a total waste....

 

[1KoolBee]

The term "Sure Grip" is a brand name that the Chrysler Corporation used to describe their limited slip differential. General Motors had brand names for theirs, Ford and AMC did too.
You could have a clutch or cone type and the term Sure Grip would still apply.
My experience.....Many called the 8 3/4" cone type limited slip the "Auburn" unit since they were known for producing those. The Dana Power Lock uses replaceable clutch discs to facilitate the limited slip action and is often preferred since it is rebuildable.

What KD said. 8.75 Dana Power-Lock will fit in 741, 742, and 489 cases with proper bearings. In fact I’ve pirated one from a 741 case and put it in a 489. It’s the baby bro of the 9.75 D60 power-lock. “anti spin” cone type is ok until it wears out, then it’s junk. You can “tune “ the preload of a power lock by varying the number of concave clutch plates in each side.

 

[1KoolBee]

Yup but the cone unit can be machined to work again if the guts are not a total waste....

How do you correct the lash of the spider gears if you machine the cones? Shim the spiders?

 

[33 IMP]

How do you correct the lash of the spider gears if you machine the cones? Shim the spiders?

Pretty sure there are tutorials both here and A-bodies. I even think Cranky might have wrote one.

 

[Cranky]

How do you correct the lash of the spider gears if you machine the cones? Shim the spiders?

If it's the first time to machine the cones, I don't worry about them but anything after, I'll shim them. Used to get my shims from the Ferd dealership. Also, don't machine more then .025" from the cone's faces.....no need to go more than that and will last for many years. Years back someone said to machine them .100" but all that does is makes them .100" thinner.