You shouldn't need to pull it... Especially if there's a motor plate back there.
You should be able to shine a flashlight up between the converter and flexplate and see any REALLY loose bolts. Assuming the threads were clean when it was assembled, you may be able to use a long straight screwdriver and turn a loose bolt as well. You could also try and wiggle the flexplate fore and aft. If a bunch are loose, you'll feel it 'tick' back and forth on the bolts.