12 bolt rear end

[bowtie81]

Is there anyway to tell what series carrier a 12 bolt has without taking the cover off? I have a 12 bolt out of a 66 chevelle with 456, i want to change to 410 but i dont know what series carrier it has to order gears.

 

[tnts79]

If it came with 4.56's is probally a series 4...? The 4.10s shouldn't be a problem. There should be a code stamped on the axle tube near the housing, that will tell you factory gear ratio etc...