This is the glove box label with *ALL* options it was built and left the factory with.
This is #1 Son's place and is based on this forums postings
#1 Son's place
The RPO code page from #1 Son's place. Look up the various codes from your glove box label
and the diff ratio will come up. NOTE that if this is a used vehicle, the previous owner could
have changed out the diff gears, so that label will now be wrong.
RPO Codes
Best then to tape a length of string on the drive shaft. Mark/note a datum, I like pointing straight
down. Roll the vehicle one tire rev using the valve stem as the datum. Count the number of whole
turn and fraction of turns. That is your diff ratio. Remove the string...