Opinions on a 8 3/4

[rog_allen]

Curious ....
I pulled the center section out of a 68 newport and i'm wondering how good these are ? I dont know if this was ever changed or if is original
the cast says 2881489 ,, it has 10 splines on the yoke.. Its a sure grip .. The ring gear is stamped 323
i heard there are a couple difrent sizes.. Is this a bigger one ? Do these hold up good ?

 

[racedodge]

489 case has the biggest pinion diameter and the 3.23 is a good all around gear to have. Now, whether or not you have a cone style or clutch style suregrip determines whether or not it is a suregrip unit that is easily rebuilt or not. Not sure what you mean by "bigger", and all the cases held up good.

 

[rog_allen]

489 case has the biggest pinion diameter and the 3.23 is a good all around gear to have. Now, whether or not you have a cone style or clutch style suregrip determines whether or not it is a suregrip unit that is easily rebuilt or not. Not sure what you mean by "bigger", and all the cases held up good.

oh good it is the bigger one.. Thats what i was talking about is the pinion shaft and hopeing for the bigger one..
Dont know if it is the cone type .. The sure grip part is sealed and i couldnt see inside it

 

[rog_allen]

This is a picture of one i found and its the same as the one in mine .. It said on the picture that it is a sure grip (clutch type "power lok") differential
then it says (this is the one to buy!)

 

[rog_allen]

I bought new axle bearings with the plates made onto them.. They are a sealed bearing and no axle end play to ajust.. Think they are called green bearings
any of you's running this type and how good are they ?? Any problems ?

 

[rgp266]

Lots of folks are partial to the 742 (clutch) type of sure grip unit saying the cone type can't be rebuilt. Cone style can be rebuilt but it takes a bit more effort because machining is involved. Check your pinion spacer, is it a spacer and shims or is it a crush sleeve? If you are going to drive a car hard with the 489 case set-up you are best to use a spacer and shims. Crush sleeve can continue to "crush" under severe loading, such as drag strip launches, alowing the pinion to "climb" the ring gear. This can lead to binding and breaking teeth off of both gears. I saw this happen with both a 9" Ford and a 489 case Chrysler with the crush sleeves.
Green bearings are designed to go in a straight line only. They don't like to go around corners at all. If you are going to drive the car on the street a lot you would be, in my opinion, much better off with the adjustable bearings. This is probably going to set off a fire storm of protest but this is what has been hammered in to my head for the past 40+ years and so far, knock on wood, I have not had an axle bearing go bad on me. My 2 cents worth......
Bob