Hi, the sloshing sound is normal because of the balance ring which has liquid in it...
I would be concerned about your door latch wax motor ( part # 12002535) though... See Neptune Help
for more information about replacing the faulty wax motor with brown colored actuator tip before it damages your machine control board. When the wax motor shorts out it will blow the Q6 triac and then the R11 resistor will burn and your door probably won't lock anymore as indicated by the door locked light not coming on. The next thing you will notice is that your clothes will be soaking wet after the wash cycle because the spin cycle will not work if the door does not lock...
Your machine control board is located above the dryer on the right side.
Every Maytag Neptune front loader with a timer knob (non digital) has a wax motor and all of them shipped with faulty one except the later 2000 series stacker models. You should proactively replace the wax motor with the new design (with black tip) to prevent the Q6 R11 failure on the control board. If you're too late you can try the STAGE 1 repair kit at the same site above.
To inspect your door latch wax motor on the stackers you:
? Unplug machine
? Remove the (2) screws holding center panel and remove panel
? Remove the (1) center screw holding the top panel located inside compartment above washer
? Remove the top panel to expose the door latch assembly
I hope this helps you.