I may be misunderstanding what I am reading, but from a post I read about differential interchanges and from Mazdatrix, it seems I cannot put an 85 differential in my 83 axle (Both are not LSD). If this is true, why are the carrier bearings the same for all 797-85 differntials? I thought they were not interchangeable due to axle size. Will it work, or is there something else different?

 

i could be wrong on this but i believe it is because of the different size axles from the 81-83 LSD's and the 84-85 LSD's

 

79-83 are "small axle" housings.
84-85 are "large axle" housings.

The entire axle is different, from the diameter at the splined end all the way to the diameter at the bearing end. This means there is no physical way of putting the bigger axles into the earlier housing.

I understand the diff carrier bearings could be the exact same part. It's the splines inside the side gears that dictate which axles fit.

 

Thanks for the help.