Besides tag, how do I know what diff I have?

[diamondplate]

I was thinking of changing out my rear differential fluid on my '06 and I am unsure of which diff I have. Apparently, there were two versions offered in 2006 (not sure of other years) - the Dana 80 and the standard Ford unit. I just want to be sure I am putting in the correct fluid type.

Basically my whole undercarriage was spray bombed with bedliner by the previous owner. It is so heavy on the diff that I can't read the tag.

Thanks in advance-

[jimmyv13]

It's listed on your door jamb sticker....bottom row.

[sinner6.0L]

dana 80 = dual rear wheels

the ford 10.5 rear axle doesn't take 75w-90 it takes 75w-140 synthetic

[diamondplate]

Thanks guys-