Remove the front panel by removing the two screws at the bottom of the front panel and swinging the front panel out from the bottom to disengage the spring fasteners from the top cover.
Remove the belts and inspect them.
Turn the large drive pulley by hand CCW (looking at it from the bottom). If the pulley will not turn, the transmission has to be replaced.
Post the results.
Here are the breakdown diagrams and Replacement parts for MAYTAG LAT8404AAE WASHER-TOP LOADING | AppliancePartsPros.com