Thanks Jake, I almost paid $18 for that manual.Hi,
Here's the service manual for your model: www.applianceblog.com/manuals/MaytagNeptuneStack.pdf
I remember having a similar issue, and replacing the struts fixed it.
The shocks should be stout with heavy compression so it is difficult to compress. You can see if the top of the tub will easily press down onto the shocks.
The service manual will tell you how to access the shocks to check them.
Here is a new shock strut kit for your model in case you need to order it:
Shock Absorber 22001988 Order now for same day shipping. 365 day return policy. RepairClinic.com
I took a chance and ordered the struts already. Sounds like I'm on the right track. The struts are very loose and move up and down very easily. It turned out the banging noise was the drain hose hitting the back of the machine while it was doing the jig in the laundry room. Thanks for the help.