Hi,

I'm wondering if there is something
else holding it on.

Yup, usually rust

A copy:

Changing a pump tips: This pump (
http://appliancehelp.hypermart.net/i...iolderpump.JPG ) is
pressed onto the motor shaft. The motor shaft often starts to rust and
the shaft swells out and holds onto the pump...tightly!! Often need
to...remove power, remove the pump clips, remove the hoses from the
pump assy. if the pump assy will not lift off of the motor shaft, you
may need to remove the motor & pump together and break off the pump
assy. A hammer and flat screwdriver can usually crack the old pump so
it can be replaced. Sand/clean the motor shaft before installing the
new pump.

Your pump for the model#...

http://www.repairclinic.com/referral.asp?R=153&N=763
Washing machine discharge pump on top of motor.

jeff.
Appliance Repair Aid
http://www.applianceaid.com/