I put a small wrench right above the point circled on the dipstick. I had a piece of 3/8 steel rod bent to fit around whatever obstacles are in the way. Put the dipstick in the block, slip the wrench over the tube, position the steel rod on the wrench as close to the tube as possible, and have a helper tap on the rod with a small hammer. As long as the ridges Joe mentioned are reasonable close to the correct size it will go in fairly easily.