leaking gear oil out of 8 3/4 chunk

do i have to take it to find out if it a cone style or clutch type?
which one is better?

Yes you do have to remove the center section from the axle to find out if it is a cone or clutch type. The clutch type sure grips are more desirable because they are rebuildable, cone style are not, BUT you can machine the carrier in the cone style and use a shim kit. On another note, you will never know the difference in performance vs. the two. they perform the same, and both will last a long time....