Guess WHAAT? Yep--this Genuine GM part will work in my 2003 Silverado short bed 4.3L V6 4 w/d, BUT--there's absolutely NO ROOM to "slide" it onto that frame bracket where it should be with that bottom retaining clip.
No room at the inn "thang."
Had to cut off the bottom portion of the retaining clip (the height of the new nut was an issue) , "shave off a bit on the sides" via Mr. Grinding Wheel so the "modified" nut could easily slide in, and position it in that very narrow "slot" where the OEM nut was welded to the frame.
It works! Got 'er done.
Guys--I am in my mid 70s. I've had GM products since 1963 (first one, a '56 Chevy Bel Air Coupe @$50) but I tell you this: I've NEVER seen such damage and corrosion to undercarriage, brake and fuel lines, sheet metal, as I see now with "new" vehicles. Here in No Ohio, they use rock salt, calcium chloride, and brine from oil & gas well on winter roads--pure DEATH to the chintzy metal used on today's vehicles IMHO. I try and keep my vehicle for 20+ years--it may be impossible to do these days.