77 Bronco Rear End ID Tag Help

[352Bronco]

I need help decoding the rear end tag I've looked around but i'm at a loss so here it is.

U15GL086891 O S 13
U152 18 C

 

[Broncobowsher]

U15 is Bronco wagon
U152 is high GVW package
G is 302 engine

Doesn't look like a rear end tag to me. VIN plate?

 

[352Bronco]

Maybe I was told by it was the rear end tag and I assumed it was since there wasnt on still attached to the rear end. Little aluminum tag like ive seen on rear ends but Im not 100% sure. The first set natches the VIN up to the O S 13. The 2nd set idk what its for

 

[70rdstr]

Never seen anything other then 3.50 gears, limited or open, all 28 spline, FWIW
Eric

 

[Viperwolf1]

18=open diff, 3.50 gears

All '77 axles had big bearings.

 

[MarsChariot]

Like the title says "EVERYTHING you ever wanted to know....."
http://www.maliburacing.com/ford_9_inch/ford_nine_inch.htm