If your washer fills properly but doesnt agitate you should do the following; this will be a lot, so bear with me please.
1. After filling (with the lid open), stop the timer and move it to the spin cycle. Insert something like a screwdriver into the hole to activate the lid switch. If it starts spinning and draining, then you'll know that the belt is okay. If it doesnt do anything at this point then you'll need to pull the washer forward and drain all of the water out of the tub. Tilt the washer back to lean against the wall. You'll then be able to see if the belt is broken. stop the timer and try to rotate the agitator around manually. If it will only move an inch or so to the left and right, you'll know that the agitator isnt stripped.http://www.do-it-yourself-washing-machine-and-dryer-repair-help.com/transmission-washer-Performa.html
Here is a link that should show you how to gain access into the "guts" of the washer.
2. Next you'll need to remove the agitator. Once you pull off the fabric softener dispenser, there will be a screw you need to remove to get the agitator out. The rest just pulls up and out. After this, you will see the transmission shaft......
3. Now you need to trick the washer into thinking that it's full of water. To do this you'll need to find the clear plastic tubing that runs into the bottom of the outer tub. It fits into a plastic looking case. Turn off the water supply (and of course the tub is empty once you've started all of this), and start the cycle. You'll hear the water valve solenoids buzzing. now take a putty knife and insert it under the top panel about 4-6" from each side to release the top panel. take the clear plastic tube off the bottom portion of the tub and start blowing a steady stream of air into the tube. The agitator shaft should now start moving back and forth............. If the motor starts running, but the shaft doesnt do anything, then you have a bad transmission, and it will need to be replaced.
That's a lot to take in, and I hope it's been helpful to this point. I think the first thing in order is to just figure out "why" it's not working properly.
If you figure out the "why" and want to know how to repair it, I would love to help you if I can. Dont hesitate at all, it would be my pleasure.
Again, I hope that you have found this helpful. I have written this small troubleshooting guide while tending to a little one's nose bleed, the dog carrying out the trash from the bathroom, and a glass of milk spilled all over the kitchen floor. thank you and let me know how it turns out.