Sure grip resto

[Belgium R/T -68]

This propably a question put before but I have problems to understand the servicemanual when it comes to rebuild my -489 and -742 suregrip.
Maybe because they always refers to special tools and my technical english isn't perfect. Is there any threads anywhere who could help me and also
describe the difference between the 2? I see in the -489 Ring and Pinion installation kit there is this "spacer" included and not in the -742 kit.

Would really apreciate some help.

//Per

[resq302]

Easy way to tell the two apart is the casting numbers on the housing will end in either 489, 741, or 742.  The spacer is actually a crush sleeve that collapses to set the preload on the pinion gear.  As you can imagine, it is a one time use only.  Most people change this out to a solid spacer and just have to shim it.  That is what I did with mine when I sent mine out to have it rebuilt.  This way, if you have to change out the u joint yoke, you dont have to pull it apart and replace the crush sleeve.

Also, the main difference between them is the diameter of the shaft for the pinion gear.  The 489 case would have something like a 1 7/8 diameter shaft.  The 742 is a stepped size shaft, and the 741, I think is a smaller diameter of all 3.

[Belgium R/T -68]

The sleeve included in the installationkit from Richmond, would that be a solid or a crushsleeve?

[resq302]

I would call them and find out to be sure.  Probably if it was a solid spacer, I would assume it would come with an assortment of shims.  But, ive been known to be wrong before.

[Belgium R/T -68]

Indeed a lot of shimes came with it but I will check anyway. My problem is the play between ring and pinion, could it then be enough to adjust only the backlash and leave the pinion like it is?

[resq302]

Don't know.  I did not set mine up.  Rather pay someone to do the work for me and then know it was done right.

[Belgium R/T -68]

I have also read that the -489 has one type wich is not rebuildable, how do I know I don't have that one and what makes it unrebuildable? Can't
you even change gearratio in it then? 

[Ghoste]

You can change the gear ratio.  The older Sure Grip units (742) had a series of clutches inside which could be replaced.  The newer 489 style has a cone clutch arrangement which was not designed to be rebuilt.  To determine if you have the cone type, just look in the side of the SG unit and see if you can see some coil springs in there which look remarkably like valve springs.
Anyway, whichever you have, it can be changed to the other style or exchanged for a new one and you can take the ring gear off of it to change ratios.

[Belgium R/T -68]

What about only setting the backlash and don't mess with the pinion, that beeing my problem?

[Belgium R/T -68]

The -489 is OK, I meassured backlash to 0,006" and the rest seems good. The -742 on the other hand needs a new Ring and pinion but that type
shouldn't use a crushsleeve I understand, would that make life easier?

[resq302]

For what its worth, I would change out the crush sleeve with a solid spacer and just have it shimmed to the propper tolerance and keep the 489.

[firefighter3931]

For what its worth, I would change out the crush sleeve with a solid spacer and just have it shimmed to the propper tolerance and keep the 489.

The 489 with a solid spacer kit is bulletproof. Once you disassemble the 489 case you need to use a new crush sleeve or the spacer kit....pinion pre-load is set when torquing down the pinion yoke and the sleeve "crushes". The solid spacer with shims is more reliable.



Ron

[resq302]

If you are concerned about the sure grip cone type for the 489, what I did with mine when I had mine rebuilt was swap out the clutch type sure grip from my 742 case.  This way, your 489 case would not only be bullit proof with the upgraded solid spacer but also now have a rebuildable sure grip unit.

[Tilar]

You can change the gear ratio.  The older Sure Grip units (742) had a series of clutches inside which could be replaced.  The newer 489 style has a cone clutch arrangement which was not designed to be rebuilt.  To determine if you have the cone type, just look in the side of the SG unit and see if you can see some coil springs in there which look remarkably like valve springs.
Anyway, whichever you have, it can be changed to the other style or exchanged for a new one and you can take the ring gear off of it to change ratios.

If it has the springs, which one does that make it?

[Ghoste]

The cone type.

[Lifsgrt]

I believe to swap the clutch-type diff from the 742 to the 489, you'll need new carrier bearings for the clutch-type diff to fit into the 489 case.  Good luck.

[Chatt69chgr]

If you surf around on the net you can find a good work up on the different "chunks" that came in the Chrysler 8-3/4 rear end.  Of course, they were the 741, the 742 and the 489.  Correct that the 489 used the crush sleeve to set the pinion preload.  Can be replaced with a solid spacer and shims from RATech.  The suregrip can be interchanged into any of the carriers.  Just need to match up the carrier bearings as mentioned.  And yes, the best course of action is to use the 489, put solid spacer in instead of crush sleeve, and install the clutch suregrip into that carrier.   Best of all worlds.  Note that Chrysler still sells the rebuild kit for the clutch type suregrip.  Note that some have actually rebuilt the cone type suregrip.  Have to remachine the ends of the cones.  I would still use the clutch type. 

[mikepmcs]

maybe this info will help clear some stuff up.

http://www.mopar1.us/875.html

http://www.mopar1.us/setuprear.html

http://www.mopar1.us/875rear.html

lots of good stuff at this last link as well.

http://www.moparts.org/Tech/Archive/axle.html