8 3/4 sure grip

[65cgretired]

need advice, 65 belvedere 11 with 742 sure grip will spin both wheels on surfaces like sand, loose gravel, grass, but does not on concrete or asphalt. am I looking at rebuilt of diff.

 

[66Satellite47]

Probably

 

[khryslerkid]

Have you ever done anything to this rear, like you just installed it, ect.?

I've known that with just the limited slip oils, they aren't enough to make the clutches work. Then after adding the right additive they grab fine.

Dr Diff recommends this and only this (XL3). He stated to me that other brands break down after awhile. You can get it at your local Ford dealer.

 

[66Satellite47]

Very good point, although usually lack of the friction modifier also has chattering of the sure grip.

 

[Cornpatch MO]

need advice, 65 belvedere 11 with 742 sure grip will spin both wheels on surfaces like sand, loose gravel, grass, but does not on concrete or asphalt. am I looking at rebuilt of diff.

I understand the 742 sure grip has clutch plates that are rebuildable. My question is, can they be made to grip more than stock , and how to do that. ........................MO

 

[493 Mike]

Hi fellas, I have replaced several sets of Sure Grip clutches (be sure to have axle shafts installed before tightening case halves) with out any issues. They have all locked up when the demand arose. I do not envision any way to improve on the design. Of course all the components have to be in good shape.
Mike

 

[66Satellite47]

I rebuilt mine a couple of times. Don't know how to increase clutch grip. Just be sure the clutches are installed in the correct order & as 493 said make sure to put an axle in each side to line the clutches up properly. Also be sure to use Loctite on the left hand threads to keep them from backing out. Use one of the friction modifiers designed for this type of differential.

 

[5.7 hemi]

Dr. Diff has a more aggressive set of clutches for that sure grip, but be warned, they will chirp the tires on every single turn you make. I got tired of hearing it, went back to the regular set, much better.

 

[YY1]

I was surprised to see not 2 but 3 different name brands of gear lube with "limited slip" additives already mixed in straight from the factory the last time I went to O'reily's.

Back about 1990, you couldn't find anything to save your life unless you went to the dealership and paid through the nose.

 

[Cranky]

Have you ever done anything to this rear, like you just installed it, ect.?

I've known that with just the limited slip oils, they aren't enough to make the clutches work. Then after adding the right additive they grab fine.

Dr Diff recommends this and only this (XL3). He stated to me that other brands break down after awhile. You can get it at your local Ford dealer.
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All the years I've been building rears, I've never seen this happen. It might work on one that's close to being worn out but it's not a cure all. The additive is mostly an anti chatter modifier. Heck, I've even used STP in one where nothing would make it quit chattering but the STP did.....

need advice, 65 belvedere 11 with 742 sure grip will spin both wheels on surfaces like sand, loose gravel, grass, but does not on concrete or asphalt. am I looking at rebuilt of diff.

You might try what kid said and see what it does. If it doesn't work, quit trying to make it work because you will only cause damage. Cone type or clutch type, they are not designed for one wheel peel and they will both turn into junk in short order. If it's a cone unit, even though there are no repair kits, they can be machined to work like new again. I've brought many of them back to life over the past 30+ years.....