PML offers two covers for the Dana 80 differential so that folks can select the cover that works best for a particular vehicle. Generally speaking, the straight fins cover was designed with 1999 and older trucks in mind and the patterned fins cover with new trucks.
Here are the differences between the two covers:
Both covers hold about the same amount of fluid over stock. The straight fins cover is deeper than the patterned fins cover, but it has a round pumpkin shape so it only holds a few ounces more than the patterned fin cover.
For the matching front covers: See part number 10737 (has steering linkage clearance) or part number 9426 for matching patterned fins or part number 6063 for straight fins.
Volume: stock capacity to qts. over stock
Dimensions: Click here for dimensions. Check size, shape, number of bolts, level check hole location, axle rotation, vent if any, and clearance.