323 rear end??

[my1st68charger]

i have a 323 rear end for my charger,I was told there were 3 different kinds of 323.Something about the pinion different size or somthing  .I was told the last 3 numbers of the case will tell you the difference ,mine says 742 .Any ideas on this??

[John_Kunkel]

The 742 has a straight 1 3/4" pinion stem, many (myself included) consider this the best of the breed.

The 741 has a smaller straight stem and the 489 has a larger tapered stem. There are two other earlier casting numbers that are basically the same as the 741 and 742 so there are actually 5 different casting numbers.

[my1st68charger]

Thanks for the info,I picked this one up for 200$ housing and axles,its a bonus to find that info out!!!

[c00nhunterjoe]

742 is the most desired due to the sure grip being clutches vs the 489 case's cones. the 742 is cheaper the rebuild as you just replace the clutches. if a suregrip goes out of a 489 case chunks of cone go everywhere in the rear and you cant rebuild them, you have to buy a new one

[my1st68charger]

This  one is not a suregrip but it says 742    ?

[John_Kunkel]

All of the 8 3/4" Sure-Grip units are interchangeable, what makes the 742 more desireable is the larger rear pinion bearing, it makes the pinion more stable when under load.

[Just 6T9 CHGR]

Also the fact that the 742 uses a solid pinion spacer with shims where the 489 uses a crush collar to set the pinion pre-load....some feel this crush collar design can loosen over time....

Im actually in the process of changing out my cone type Sure-Grip unit in my 489 case for a new clutch type....

[my1st68charger]

When I got mine it was apart ,the crown and pinnion are nice but I couldn't turn the spider gears.So I took it apart and found the shim between the small spider gear looked damaged,the center is like oval on one shim and the other looks like someone put it together wrong ,almost like the shim was out of place and they contiued to drive the pin in anyways.I think if I get new spider gears I should be ok.

[Chatt69chgr]

The clutch type suregrip can be interchanged from any of the three 8-3/4 differential housings.  I believe the carrier bearings are specific to the housing.  So if you use a clutch type suregrip from a 742 housing in a 489 housing you would need to use the carrier bearings specific to that housing.  RATECH makes a solid spacer and shim pack to replace the crush sleeve for the 489 housing if you don't want to use the crush sleeve:

http://www.ratechmfg.com/chryslerspbs.htm

[John_Kunkel]

The carrier bearings are specific to the carrier, not the housing. The carrier bearings all have the same OD but the ID of the bearing differs with the carrier.