8 3/4 case questions #$@%^*&

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mycuda

mycuda

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Hi, looking for some answers before I have an anuerysm.

I remember years ago I had A street gear and race gear setup for 8 3/4.
I would change them out as I wanted. One was a 489 4.10 suregrip, other was a
741 2.76 suregripI believe. When I would change to 741 I would have to put
"buttons" at axle ends to rid excess play.
Current project put early b body 8 3/4 in abody done many times before.
However it came with 489 open 3.23 which I sold. Went to put in 742 series suregrip
and found out 1/4 inch play both sides.
I obviously need the buttons or shims to work.
Is there a rule of thumb with series case of 8 3/4 and shims or is it strictly the type/year of car
and axles that determine this.

Thanks Dave
 
If the car is '69 or older it has (or had) tapered wheel bearings which are adjustable, and require the button in the diff.
If the car is '70 or newer, or is an older car that has undergone the "green bearing" conversion, it has ball bearing wheel bearings which do not require the button in the diff. Typically with the green bearings the button is removed.
Now you might be even more confused. I hope not.
 
As mentioned if you have adjusters with the tapered bearings you have to use thrust buttons. With the ball bearing sealed type bearings you don't use thrust buttons. Though the clutch style sure grip and the cone style use two different style thrust buttons. The case number really has nothing to do with it. Perhaps if you posted pictures of you axle bearings we can narrow the choices down for you.
 
Buttons are different for cone and clutch sure-grips as well.

Cone used a captured block type and clutch used a 2 piece pinned type.
 
But what would explain 1/4" of play on each side? That doesn't seem possible under any circumstances.
 
Without seeing it or pictures, I would guess you have taper bearings and your missing the thrust buttons.
 
Just was wondering because I have used tapered bearing axles with the adjuster and did not need
Thrust buttons on certain case series with sure grips older than 69.

I will be getting the green bearing kit for my current issue.

Thanks all.
 
mycuda said:
Just was wondering because I have used tapered bearing axles with the adjuster and did not need
Thrust buttons on certain case series with sure grips older than 69.

I will be getting the green bearing kit for my current issue.

Thanks all.
Click to expand...

I think you have it backwards. As mentioned earlier the cone type sure grip didn't have thrust buttons like the older clutch type sure grip. It has a captured block in the middle instead but it does the exact same job the thrust buttons did. The cone type sure grip was only used in 489 cases from the factory starting sometime in 1969 although they can be installed in any 8-3/4 case.

By the sound of it the 742 you have is just missing the thrust buttons. Unless they become worn and beat up they usually stay in place in the sure grip so the times you didn't have an issue they were in place
 
.........The thrust block in the cone type sure grip is 1 1/2 in wide, same width as an open rear.......the clutch type buttons measure 1 3/8 in.......kim........
 
Ok. Thanks for the education on year/ cone/clutch type 8 3/4 suregrip case.

My headache is going away now........

Dave
 
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