Being a 450 series, it will have a "GMC PARTS IDENTIFICATION" tag on the back of the glove box lid that will tell you if it's a OD or not. The tag has all your trucks spec'd eng., trans., axles, info. stamped on it. It will either say 5 spd. DD, or 5 spd. OD. I own a 1952 GMC F473-30, COE.