Not a chain on the wipers. There is a square piece on the motor that fits into a slotted piece on the wiper pulley. Just had to do some bending on the motor mount to get a good fit. Seems to work as it should except for reattaching the cables. I had taken them loose from the pulley and couldn't figure how to get them back on. Found a great article on the net how to do it. But it takes two people to do it unless you have 6' arms. Seems as tho you remove the blades arms and depress the knob. That releases the spring loaded pulley on the bottom of the stansion. As the knob is pressed you pull the cables. That gives you the slack to hook them back up. Then you press the knob again and the spring retracts and tightens the cables back up. Like I say two people or 6" arms.