The navigator had an independent rear suspension. It has struts in the rear like you have in the front suspension of your truck. Your rear axle is solid and runs on leaf springs. It wouldn't work. People replace the air springs with replacement struts as they fail:
2009 XLT (XTR pkg) supercrew 5.4l 6sp 6.5ft bed.
110k miles, Raider Topper, Ride Rite airbags, Ford well liners, 5Star SCT Tune, NGK Iridium IX plugs, Bilstein 5100s all around.