This is in your transmission box, it controls agitate and the drum really shouldn't ever drop. The outer drum is suspended by shocks if you mean the whole thing drops that is normal, if you mean the inner drum drops .... that's in the transmission and not normal
The transmission is W10330039 and you can order it from 1-888-464-2853 or your welcome to google the part number.
It's not super hard for you to install but It will take a special wrench to remove the tub. It's part number TB123A
How much is a new transmission?
You need to remove the agitator and take the nut off the drum ... I usually leave it intact. When you get the new transmission you will see how it bolts to the bottom. With that nut removed you should be able to drop it from the bottom without actually removing the case
Depends which market your in around 250