[2003YZ]

My Sonoma has a 3.08 8.5" (code G80) gear with the poop Eaton Gov-Lok diff. I need to change to a 3.42 using Richmond gears and change to an Auburn diff. Will a 8.5 Auburn unit fit in my housing? Where can I find a code for number of axle splines? If I have to pull the axles, thats no big deal though. Sorry for the book.

 

[Twin-10s]

first u need to find out if u have 8.5" or 7.625" rearend click here for a pic of both. if u have a 8.5" yes the 8.5" auburn may work if its a 7.625" it will not.
7.625"= 28 spline
8.5"= 30 spline i think.

 

[2003YZ]

Thanks. Mine is the middle pic.

 

[Jay72]

When you order the posi they should ask you what year the truck is, for the record earlier 8.5's had 28 spline axles, after sometime in the 80's they changed to 30 spline.
I've noticed jegs and summit list the older ones most of the time, just be sure to point out what year you have to the sales person from where ever you order it from.