I Have a 1985 f250, 6.9L, Dana 70. Can I use a Ford rear axle in this truck. If so, what do I have to look for. Thanks

 

by ford rear axle you mean sterling 10.25? either way yes, the u joints might be different size caps but other then that, your good to go.

 

it is 2wd right? if its 4x4 you gotta make sure the gears match or when you do throw it into 4x4 your gonna bind up and break something

 

Where is the fill plug located?

The Sterling axle looks a lot like the Dana 70.

Dana axle fill plug in the rear cover.
Sterling axle fill plug on the drivers side of the pinion on the front of the axle.

 

Also, make sure everything in the replacement axle matches, spring perch to perch measurements and backing plate, to backing plates can also differ, depending if it came out of a dually, cab and chassis, or regular truck.