8 3/4 Sure Grip Info

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ram250098

ram250098

69 Barracuda
Joined
Nov 25, 2007
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Cookstown Ontario Canada
I am still trying to figure out this Demon of mine. It has the 8 3/4 rear 741 case. I find it odd that a 72 340 four speed demon would not have suregrip, was this fairly common in cars like this?
AL
 
ram250098 said:
I am still trying to figure out this Demon of mine. It has the 8 3/4 rear 741 case. I find it odd that a 72 340 four speed demon would not have suregrip, was this fairly common in cars like this?
AL
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How do you know it's not a SureGrip?
 
ram250098 said:
By that single black mark in my driveway LOL
To be sure I jacked up the rear and gave the wheels a spin...yup they spin opposite.
AL
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Well Al, a friend of mine bought a brand new 1970 340 4 speed Duster. He didn't order the SureGrip and it came with a one wheeler. So, they did come that way new. You can install an Auburn unit in yours to make it a posi.
 
I have the Auburn Pro Series in my car and it works well. But it is not rebuildable. The Power Lok clutch type sure grip, which is rebuildable, is now being reproduced and can be had on ebay for about $339. The Power Lok was not being reproduced at the time I had my rear done that is why I went with the Auburn.
 
340sFastback said:
I have the Auburn Pro Series in my car and it works well. But it is not rebuildable. The Power Lok clutch type sure grip, which is rebuildable, is now being reproduced and can be had on ebay for about $339. The Power Lok was not being reproduced at the time I had my rear done that is why I went with the Auburn.
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Yukon makes the most reliable Power Loc unit. Don't know who's making the ones on e-bag. I believe Yukon is a re-pop of the original Dana Power Loc. But, anything is better than a one hopper.
 
Randys Ring and Pinion has the Yukon Power Loks for $460. I guess those ones on ebay are Chinese copies? Probably better off paying more and doing it right the first time. While the Auburn in my car works great I would definitely be buying a Power Lok instead now that they are available.
 
I have an Auburn in mine also,spent the big Can$$ It,s new and I,m happy!My account isn,t!The 8 3/4 is the best to have in your street car,you.ll be able to tell by prices of sure-grips!
 
340sFastback: You're right about paying more and doing it right the first time. Power Locs are the way to go with an 8 3/4 rear. The Auburns are OK as long as you're not driving big horsepower through them. The Auburn is a good unit for a street car.
 
How difficult is it to set up the rear gear pattern once you install one of these units into an open rear? Does it require any special tools like dial indicators etc?
Last diffy I had rebuilt, I had to have a pro set the pinion depth on my 12 bolt Chevy. I know next to nothing about setting up a Chrysler rear end.
Thanks,

George
 
George R said:
How difficult is it to set up the rear gear pattern once you install one of these units into an open rear? Does it require any special tools like dial indicators etc?
Last diffy I had rebuilt, I had to have a pro set the pinion depth on my 12 bolt Chevy. I know next to nothing about setting up a Chrysler rear end.
Thanks,

George
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Same type of thing as your Chebby. All need the pinion depth set. You'll need some special tools to set up any rear. Dial indicator, Torque wrench,( ft. lbs. and inch lbs.) yoke holding tool. Isn't hard to do if you have some patience.
 
I had to have mine shimmed do to backlash?It,s hard to find a good USED sure-grip,cause I don,t think there,s one out there that hasn,t been pounded?If someone is selling one and tells you different,there lying!
 
pettybludart said:
I had to have mine shimmed do to backlash?It,s hard to find a good USED sure-grip,cause I don,t think there,s one out there that hasn,t been pounded?If someone is selling one and tells you different,there lying!
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You mean you had to have yours shimmed to get the gear pattern correct? Shimming sets the pinion depth. The four essential diff adjustments are pinion depth, pinion bearing preload, backlash and carrier bearing preload. No matter what rear is being set up.
 
If all you are doing is putting in a sure grip on an open rear that is in good condition then you'll only need to set back lash and carrier bearing pre load which is not too hard on an 8 3/4. But with used gears you should set back lash up to where it was or its going to make noise.
 
Demon416 said:
The Auburn is a good unit for a street car.
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Yes it is and the Pro Series has bigger cones in it then a stock mopar sure grip. I can go around a right hand curve give it gas and both wheels will spin. It is definitely doing its job. But I like the Power Lok better since its rebuildable.
 
340sFastback said:
Yes it is and the Pro Series has bigger cones in it then a stock mopar sure grip. I can go around a right hand curve give it gas and both wheels will spin. It is definitely doing its job. But I like the Power Lok better since its rebuildable.
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340sFastback: I agree, I've used Power Locs for years. If you happen to "puke" one, just rebuild it. If you trash an Auburn, it's junk!
 
340sFastback said:
You'll need a dial indicator to set back lash. Summit sells a good one for cheap.
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My Tranny Guy is setting backlash,cause he installed in my ..489 case.I don,t have the tools or the no-how.I,m just a grease-monkey,wrench cranker,learner.I,ve learned more on here reading than I would have learned in 20 years!Thanks to FABO fellow wrenchers.
 
pettybludart said:
My Tranny Guy is setting backlash,cause he installed in my ..489 case.I don,t have the tools or the no-how.I,m just a grease-monkey,wrench cranker,learner.I,ve learned more on here reading than I would have learned in 20 years!Thanks to FABO fellow wrenchers.
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Hey pettybludart: We all had to learn along the way. I've learned some new things here also. Great site.
 
I have the Auburn in my car and I get quite a bit of wheel hop when I turn a tight 90 in town , I was told it would loosen up a bit over time but not yet , it's fun to hammer the right hander tho- the car gets real loose reeeal quick which is fun till a cop sees me then I expect the fun is going to end If I ever have to replace it I will definetly avoid the cone type and go for a rebuildable style of unit
:munky2:
 
I bought a powerlock from www.doctordiff.com. I had him press on the bearings, and orderd a bottle of friction modifier. He was easy to work with and sent my unit out really fast. Now my Demon is laying 2 stripes. I can't wait to see how much it will knock off my time at the strip! I would definitely buy from him again....A+ vendor
 
George R said:
How difficult is it to set up the rear gear pattern once you install one of these units into an open rear? Does it require any special tools like dial indicators etc?
Last diffy I had rebuilt, I had to have a pro set the pinion depth on my 12 bolt Chevy. I know next to nothing about setting up a Chrysler rear end.
Thanks,

George
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George, although you do need some specialty tools to set the pinion depth, changing the rear from an open to a SG will not change the current pinion depth of the open set up. You should be able to dis-assemble the rear, keep the shims in place that set it in the first place and re-assemble it just like you took it apart and just add the suregrip unit. Of course you should still check the wear pattern with some set up cream, and this is only good for the shimmed units like the 741 and 742 case, as the 489 uses a crush sleeve to set the pinion depth, although they now have a hard spacer to replace the crush sleeve. Not a hard job to do, but I wouldn't DIY unless you are going to be perfectly comfortable with your work. Hate to go back in right away!!! Good luck, Geof
 
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