Ok a while back when I looked up the axle code for my 77 bronco which is B8 it listed as limited slip 2900lb. axle with 3.50 gears. "Now wait a minute I know my rear axle is a big bearing it has 11" brakes." I'm still a little confused but I'm 99.9999% sure all 76-77 bronco have big bearing axle housings. Take a look at the below pictures. they should explain a bit more. I assume someone at Wild Horses really took the time to really research it which is way they have the replacement axles for different years.