building 8 3/4 489 section

[Buschi340]

ordered now the 4.86 in combination with an eaton true trac.
guess because of me super short first gear I also should change tires from 26 inches to 30"? first gear is 3.25:1

 

[Buschi340]

btw,
checking 8 3/4 489 case rebuild kits on DrDiff page. they ask for two Options for carrier/sure grip types

Carrier/Suregrip Type

The size of the carrier bearing depends on what carrier you have.

• Clutch suregrip or pre-1969 open differentials (1.8" bearing journal)
• All others (2.0" bearing journal)

IF YOU ARE UNSURE WHICH DIFFERENTIAL YOU HAVE, PLEASE MEASURE THE BEARING JOURNAL DIAMETER.

where do I measure to determine what I require? I have an empty case on the bench. plane, nothing inside

 

[JBurch]

btw,
checking 8 3/4 489 case rebuild kits on DrDiff page. they ask for two Options for carrier/sure grip types

Carrier/Suregrip Type

The size of the carrier bearing depends on what carrier you have.

• Clutch suregrip or pre-1969 open differentials (1.8" bearing journal)
• All others (2.0" bearing journal)

IF YOU ARE UNSURE WHICH DIFFERENTIAL YOU HAVE, PLEASE MEASURE THE BEARING JOURNAL DIAMETER.

where do I measure to determine what I require? I have an empty case on the bench. plane, nothing inside

You need your new carrier in hand to determine what bearings you need; the carrier defines the bearing needed.
Since you have an empty case, the pieces you select, in this case the Eaton-Tru-Track from post #51 is the bearing definer. Dr. Diff can tell you what bearings you need to load the Tru-Track into your housing.

Hope this helps.