First question:

Is it pretty safe to assume an '04 truck w/ a 10-bolt diff has a 8.6" ring gear size?

From what i can tell, GM went from 8.5" to 8.6" rgs sometime between 1999 and 2000.

Does that sound correct?

Second question:

Would an 8.5" rgs posi (G80) from an OE 10-bolt be compatible w/ the 8.6" rgs 10-bolt?

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Starting my research on upgrading my open diff to limited slip...