It is the correct 3-speed transmission for a 54-56 pick-up. It should work up to 1964 in a truck.
It is a light duty piece so don't try to race with it.
edit: looking at the TAAA on the side cover means it might also fit in a 1953, not sure. Although the case looks the same as a car transmission the input shaft and gear ratios are different.
http://ford-y-block.com 20 miles east of San Diego, 20 miles north of Mexico