Removing a Tranny Dip Stick Tube

They can sometimes be a real pain to remove when O-ring gets hard with age. I have sprayed O-ring area with penetrating oil and then used thin jawed vise grips clamped into top of tube and then twist/pull with vise grips. If it's really stuck, I have taken a long prybar from underneath car, and put end of prybar on dipstick tube attaching bracket, and hammered up on head of prybar. Sometimes with a helper, doing both at same time.