tranny identification

[trackrat79]

I was at my friends step fathers shop today and noticed a tranny sitting in the yard. After getting a closer look I think it is a tko five speed but insted of TKO printed on the case it has DKO printed on the case. Can someone tell me what this designates. It has a cast aluminum bell housing attached to it that matches a chevy gen i block I think but it looks like it is offset with the top of the tranny leaning tward the driver side and it has a cast in mount for a slave cylinder. It is just sitting out in the yard in a pile of other stuff and I could probly get it for nothing or next to nothing if I asked for it.