Found this 3/4" ratchet in a freebie box at a garage sale. Looks to me like it should ratchet in either direction depending on which side of the handle you push drive head. I can feel it ratchet once or twice, then it gets stuck. I'd like to get this to work because its made in good ol' USA, feels beefy (weighs 5.5 lbs), not some crappy Chinesium metal. It's about 18" long, 1" diameter handle. Can anyone tell me from the pics how to open the head to get to the ratcheting mechanism?