Unscrew the drain check valve from the pump body.
Disconnect the drain hose from the pump unit and be prepared to catch any water left in the pump. Disconnect the motor wiring harness plug. Unplug the machine and remove the kickplate. There is also no removable valve in the side of the separator. The wash pump cover and separator are somewhat different, and are removed with a torx bit. LATE-MODEL KITCHENAID machines are virtually the same as pictured here, with a few small differences. You may just want to think about replacing the machine. If the porcelain is chipping off the tub, then rust will continue to get into the pump seals and ruin them. NOTE: Some of these machines are starting to get pretty old. A new pump and motor unit will come with the new design. If you have a bladder-top design, it has been replaced with a re-designed system. If it's at all sticky or gritty, replace the motor.
When you get the pump disassembled, turn the motor by hand. However, if the top motor bearing is damaged, the whole pump and motor unit must be replaced. Your appliance parts dealer has impeller and seal kits. The whole pump and motor unit are easily removed with the machine in place. Vertical Whirlpool machines are direct reversing, two-impeller machines. Of course, if you're replacing the valve, it doesn't really matter you've got to disconnect the copper line, anyway. A better alternative (though it's not always possible) may be to leave the copper line connected to the valve, and disconnect the valve from the rest of the dishwasher. Make sure you have enough copper line remaining to re-connect it to the valve. If you disconnect the copper line from the valve, you may have to cut it shorter to get rid of the old brass connection fittings. This makes it less likely to fail and flood the kitchen, but it can also make it more difficult to remove and install. It is usually copper-piped right up to the fill valve. But don't forget that there may still be water in the pump and drain line, even if the tub is empty! Have a shallow pan or an old towel standing by (one that will fit beneath the pump drain connection) to catch any water left in the tub or drain line. It is normally connected to the sink drain by flexible rubber hose and hose clamps. The drain line is also usually pretty easy to disconnect. (At 30-50 bucks per service call, that's an expensive mistake) I cannot begin to tell you how many times I've been called to fix a "dead" dishwasher, when the only problem was that it was plugged into the wrong outlet. Normally the garbage disposal switch is off, so there is no power to its outlet if you plug the dishwasher into that outlet, it will not run at all. Usually the other outlet beneath the sink is for the garbage disposal, which is wired through a switch near the sink. NOTE: If your machine is plugged in beneath the sink, make sure you get the plug back into the correct outlet.