Question
I transplanted a crabapple tree about a month ago.The tree lost all of its leaves from stress, i think? is this normal and will my tree survive?

Answer
Sounds like shock from the planting. How you dug and replanted the tree may have a bearing on the shock also. Here is a link to how to transplant and replant a tree.
http://www.gardenline.usask.ca/trees/moving.html
Make sure you mulch around the tree with not more than 3 inched of mulch and water with 1 inch of water during dry spells. Place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop.