What causes a washing machine to smoke?

It sounds like you have a bad belt and it should be replaced.

Maybe its stressed.

It seems that the motor were heating rapidly that makes it to smoke. Much better if you replaced it immediately.

Its seems that your appliance is over loaded and because of that the motor stopped functioning or cannot handled overload. Its is always recommended to go through menu guidelines before using home appliances products.

Light Smoke With Burning Smell

Light, wispy smoke coming from the bottom of the washing machine indicates a problem with the transmission shifting solenoid. Smoke coming from the upper back of the machine indicates a bad fill valve solenoid. And smoke coming from the control panel indicates a bad timer motor. Replace the defective components as needed.

Other Possible Causes

Smoke coming from a washing machine could also be caused by a defect in the electrical wiring itself, but this is the least probable cause. A partially broken wire will arc over, causing the wire's insulation to overheat and burn. A hot wire may also arc over to the grounded machine, again causing the insulation to burn and smoke. Usually when this type of problem exists, there will be, besides the smoke and the smell of burning plastic, the distinct smell of ozone generated by the arcing