Jbrew

You could refer to you owners manual, should be in the glove box.

If your without an owners manual, user kd4gij has the link to download one for your truck. I'll borrow from him, I don't think he'll mind, - here yuh go, get your manual here, -

https://www.fleet.ford.com/partsands...owner-manuals/

BigEd54

My truck has 2 tags on the diff cover. One tag is stamped with model and specs per below. The other tag is stamped with gear oil spec.