Thanks for the additional input. Please correct me where I may be wrong. Disconnect the clamp from the filler tube and lift tube out of rubber fitting. From the picture above, inside the tank the filler tube appears to be about 1.5 inches long (any idea of diameter) and the spring small diameter so not very strong. Using a plastic device to hold the flap open, insert plastic tubing and pump fluid from DEF tank. Remove plastic tubing, reconnect filler tube and clamp, refill with fresh DEF. I'm not trying too oversimplify and know that care must be taken to achieve good results. I'm willing to try but just curious if anyone else has actually done an extraction and replacement of DEF using this method.