Dodge Repair: Dodge Dakota Pinion Seal, dodge dakota quad cab, dakota quad cab

Question
How do I identify which pinion seal I need for an 02 Dodge Dakota Quad cab? My choices are 8.25, 8.5, or 9.0. There are 2 markings on the differential case both with numbers and letters. There is also an ident plate attached to the differential cover that looks like it says 3.5, it could be 8.5.

Answer
Visual inspection is the easiest way to identfiy which rear axle is in the truck. The 8 1/4 has a round cover whereas the 9 1/4 has a 6 sided cover. The other two sizes you listed are not applicable to any Dodge vehicle. The tag that is on the cover refers to the gear ratio, in your case it would be 3.54.