The Stovebolt Site Forums The Shop Area Driveline Help with rear axel ID code '56 3100

I've done a lot of looking and haven't come up with an answer so I'm coming to the experts. I'm going to need to have some work done on the rear end of my '56 3100. It has a roar at lower speeds. I believe it is not original to the truck so here is a picture and the code appears to be KAS 137W87. There's also a small lettering higher and to the right that appears to be something I can't identify that looks like ?-H Oh yah, it's a 12 bolt.
More info...casting numbers on the rear end: 3896890, GM86, N

Mickey - It took me a little bit to remember where I saw the decoding details to help you answer your question, but here you go! The pics snapped below from 1983 and 1984 Chevy Parts books shows your info decodes as follows:

KAS = 1978 or 79 - C10 - 8.875 carrier with 3.07 gear set, Standard carrier (non-Posi)

137 = 137th day of the calendar year (no idea how to tell which year?)

W = Warren plant

87 = Shift code

As far as I can figure, this is correct. Others with more knowledge of the 12-Bolts may have more details. Hope this is helpful.

Dan's the MAN! I've been looking , almost, everywhere. I found "KA" for a 66-69 Chevelle but that's all. I did get the 3.07 ratio by pulling the cover and getting numbers off the ring gear.