Hi. I am a doityourselfer and have fixed this problem several times. Your washer is considered a direct drive model. The motor attaches to the transmission with a three part "coupling kit". It has 2 plastic lugs linked by a rubber ring. When the lugs break, the symptoms are as you described. This part is cheap (6-10.00) and available from most appliance parts stores. It is replaced by disengaging the motor from its mounts and slipping the new part over the motor shaft and transmission shaft. All work is done from the underside of the machine. Good luck!
mcgiver
April 2009