Larry,
The discharge elbow should have no movement. It is probably broken at or before the valves. The repair will be a little time consuming, but it is fairly straight forward for the average handyman. This repair should defiantly be done before anything is allowed to enter the waste tanks because the drain valves will have to be removed.
When repairing the broken plumbing for your waste tanks you will probably need to replace the "Y" fitting where the gray and black tanks join together. If so, I would terminate the drain pipe just below the basement floor with the fitting going straight down. It is a little more trouble when hooking up a sewer hose (I use a clear removable elbow), but the permanent elbow below the floor is commonly damaged because of the low clearance. The "Y" fitting, valves, termination cap, and any other necessary parts should be available at most RV supply stores. However, if your "Y" fitting has a 4th fitting where the washing machine drains into it, they are a little harder to find, and you may need to order it from BCS.
If you have any questions, call me. You have my number.
Gerald