is this a D70 limited slip?
 

this is what the tag says....

3 . 54 E2TA BKB
605040 L S

it has the big lug nuts and it looks like a D60 or D70 and its in a 1983 F250 extended cab longbed diesel pickup.

I jacked it up and counted ratios and its defanatly 3.54:1 but it was awful hard to turn with one wheel on the ground!