There is a "D28" in '93-'97 trucks, it's known as the "hybrid" D28/35. What's quite funny though is if you actually have this axle and tell the dude so (these days he's likely just a slave for the computer), you will never ever get the right parts for your truck (aside from parts actually inside the differential itself). If you need anything else (brake rotors, wheel bearings, seals, ball joints, anything outside of the diff housing), you must "lie" to him and tell him you have the actual D35, as the D28 selection in their computers will always result in parts for the old non-hybrid D28, which went bye-bye in 1990.