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#1001948 - 05/29/11 06:09 AM how to tell if its a sure grip or not

looking at an 8 3/4 742 case to buy. supposed to be 3:55 gears. is there a way to tell if its one wheel drive or two? anyway to check ratio also? Thanks

#1001949 - 05/29/11 06:52 AM Re: how to tell if its a sure grip or not [Re: ]
MoparforLife Offline
Too Many Posts

Registered: 01/19/03
Posts: 25196
Loc: Upper Midwest
If it is in a car or truck - Jack up the rear of the car and turn one wheel - If the other side turns the same way the same speed it is a sure grip, if you turn one wheel and the other don't turn or the other rotates the opposite direction it is not a sure grip If it isn't in a veicle ook at this.

#1001950 - 05/29/11 09:15 AM Re: how to tell if its a sure grip or not [Re: ]
Frankenduster Offline
Moparts proctologist

Registered: 02/15/10
Posts: 14907
Loc: Granite Bay CA
It appears that the case will be OUT of the axle housing.
The 2 types of SG differentials were the Dana power Lock and the Auburn. Each is unique. The Dana is the preferred because it is easily rebuildable.
Nevertheless... the quickest way to determine if it is a SG diff: The OPEN/One legger unit has large openings where the spider gears are visible. You can fit your fingers in and easily touch the center pin as well. The SG diffs have much smaller openings.

#1001951 - 05/29/11 09:20 AM Re: how to tell if its a sure grip or not [Re: ]
RapidRobert Offline
Circle Track

Registered: 11/20/03
Posts: 33003
Loc: Lincoln Nebraska

anyway to check ratio also?

The 3rd mem is out on the ground correct? Count the teeth on the pinion and the ring gear and divide the small # (pinion) into the large # (ring)
live every 24 hour block of time like it's your last day on earth

#1001952 - 05/29/11 09:26 AM Re: how to tell if its a sure grip or not [Re: RapidRobert]
scratchnfotraction Offline
I Live Here

Registered: 05/29/03
Posts: 15010
Loc: Florida
the yr and ratio are stamped into the edge of the ring gear on 8 3/4

if its out just turn it to see the stampings

if its in the car jack up one side and turn the tire..if it turns its a pegleg

if you cant turn it its a sg that is holding

if its a sg and after checking one side off the ground,then jack up the other side to check it to see if it holds

should not be able to slip it by hand with tire on

I have seen one side weak cause a smaller tire ran on one side for a while

i have seen sg worn so bad that you can turn it by hand like an open diff

if its out of the housing stick both axle in it and see if you can slip it by hand to check if its holding

#1001953 - 05/29/11 10:40 AM Re: how to tell if its a sure grip or not [Re: scratchnfotraction]
63stabamatic Offline

Registered: 09/11/06
Posts: 277
Loc: Palmyra, NY
Good info. Another way I've seen is to turn the driveshaft input. If both wheels turn the same way it's a SG.

#1001954 - 05/29/11 12:49 PM Re: how to tell if its a sure grip or not [Re: 63stabamatic]
RobX4406 Offline
I Live Here

Registered: 04/19/05
Posts: 12271
Loc: Overpriced Housing Central
Clutch style

Cone style

Note location of bolts holding two halves together on clutch style, opposite side of the ring gear. Cone they are on the same side as the ring gear bolts.

#1001955 - 05/30/11 01:53 PM Re: how to tell if its a sure grip or not [Re: ]

really appreciate all the help.


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