Sure Grip rebuild

My son's Dart already has a sure grip, but yesterday we discovered that it may not be working properly. We were working on the hydraulic clutch and wanted to make sure the clutch was disengaging. With the trans in first and clutch out he could spin one side and the other side was spinning opposite indicating that the SG may be worn out. Dr Diff has a clutch pack for $117. Is that likely all we'll need? How difficult is the rebuild?

Which type and year posi unit?
The Dana 8 3/4 clutch type posi are rebuildable, the cup and cone type are not that I know of

Is it a clutch or cone , the DR. diff kit is for a clutch, assuming you know how to set up and 8 3/4 chuck it's not hard , follow the service manual and note what the backlash is before taking the diff unit out to rebuild. I believe the case bolts are left hand thread .

They're not "rebuildable" but they're repairable. Worn cones can be machined and Doc Diff offers a shim kit.

To my knowledge it's the unit I pulled from a '68 Coronet wagon. We've swapped carriers into different third members (on the recommendation of a local gear shop) with no issues so I'm not really worried about pulling the carrier out. If this is the carrier I think it is that's what we did. The Coronet had 2.94 gears and we put the SG into a case with 3.23s.

That should be a Dana brand clutch type early posi, good stuff and rebuildable

Also a 68 power-loc will have the one piece side gears, the earlier units had two piece side gears and you would have to use the axles to align the splines before tightening the unit back together after a clutch rebuild.

Most sources show the introduction of the cone-type Sure-Grip as being in '69 but is was actually introduced on January 9, 1968. Only a visual inspection will show what it is.

Learned something new , I've only seen 2 piece side gears in the few I have owned , now I have something to look for .

It was a mid 68 thing from my understanding prior to them phasing in the non-rebuildable units.

All the Dana brand 8 3/4 posi had two piece side gears, the later Eatons did not have clutches or the same type spider gears like the Dana 8 3/4 posi units had
If you can see springs inside the posi it is an Eaton type, not a clutch type Dana brand

Cab the cone type used by Chrysler was made by Borg Warner .

Isn't Eaton currently making them? I know BW sold off alot of their designs.

I was just thinking, wouldn't it be better just to replace the unit ? might be cheaper as well

I think we've decided that it won't get done real soon. Found out the main brake line is clogged yesterday, so I guess we're doing brake lines.

I was told back when the Mopar drag team did their seminars that Dana corp. provided all the pre 1969 clutch type 8 3/4 posi units, I don't remember if it was Tom Hoover, Dick Maxwell or who now

Aren't clutches like 60 bucks?

Eaton, Auburn , BW , no matter who makes it they all have one thing in common ... GARBAGE design ...

$79 from Dr. diff withthe 2 thin plates that the factory design used , I ended having to scavenge 2 when I rebuilt one because the MP kit I got had all thick plates .

https://www.doctordiff.com/powr-lok-clutch-pack.html?variation_id=237

vs. a new powerlock at $395 ...

https://www.doctordiff.com/8-3-4-clutch-type-sure-grip-powr-lok.html

just weld up the spider gears and the clutch plates..................

Only once

Not on a street car. One of the funniest things I've ever seen was two guys trying to autocross their drag cars with spools. Making a corner was interesting to say the least. I may have video somewhere. Many of you know the name of one of them and he does hang out here a bit, Larry Gilley.

Yes, the original Sure Grip design was the Dana Power Lock. Many parts interchange with the Power Lock for the Dana 44. This is the clutch type with the 2 cross shafts.

Put Mopar side gears in my Chevy positraction unit so I could swap in larger fine spline axles. Side gears were from 65 and later as I recall.