Done this several times. Clean the area around the dipstick tube, make sure all the tranny fluid is cleaned off at the base where the dipstick inserts into the case. Take a cap of DOT 3 and pour it around the base. Let the car sit for a day. Then take it for a drive. Eventually the rubber will swell. I wouldn't do it more than once. If you replace the the o ring rub the o ring in Dot 3and insert the tube. Again let it sit before adding tranny fluids. Has worked for me several times.