The Stovebolt Site Forums The Shop Area Driveline Rear Axle Identification

I need some help figuring out what rear axle I have. I'd like to know what sort of load it is rated for. This is 57 Task Force with a 3/4 VIN, but with the wheelbase lengthened a little by cutting and reattaching the frame. So for all I know, the whole rear end could be different. But the frame rails are the same size and everything looks like it matches.

I know so little about trucks, I'm not sure what to look for. Makes googling for information challenging.

With one set of dually wheels off the ground, and one stopped, I spun the wheel 10 times, the driveshaft moved 23 to 24 times. This surprised me as I was expecting a ratio closer to 4.5-7 for this truck. Is a gear swap doable/possible such that this could be the original axle with a different set of gears? My reading on here didn't seem to indicate that any were available. Am I trying to determine the ratio incorrectly?

It's got two sets of springs. It looks like a set of 10 leafs, with an additional overload set above it. 5 or 6 springs on it, I need to recount.

After some scrapping, brushing, cleaning there is a number on top of the axle housing that says CD1129.

Anything else I can check to help identify this?

Thanks,
JFS III

According to the GM Heritage Resto Pack site, CD1129 comes up as a 3600 axle, 4.57 gears, with RPO 285 Dual Wheels. It should have 7.00-17.5 tires on it. The 10 leaf springs were a factory option, the overloads are probably aftermarket.

That makes sense to me, and is a ratio I was expecting. But I was thrown when I spun the tire and got a much different number of revolutions on the driveshaft. I would expect that if I turned the wheel 10 times, I should see just shy of 46 revolutions in the driveshaft.

Am I not understanding something somewhere? I counted roughly half that.

Edit: Nevermind... There's a factor of 2 in there, even with the opposite wheel blocked according to sources online.