You will need to go by the first two digits of the serial number to figure out the correct motor to order.
Post the first two digits of your model number if you are not sure.
You could also double check the part number on the original motor.
Post the part number of the original motor here if it don't match one below and will see if it crosses to another number.
Serial number starts with 28 order dryer motor part # 33002478
Serial number starts with 55 order dryer motor part # 33002795