Just as I was finishing the 2nd pass of the driveway,the Ariens' stopped moving. Yesterday, I took the belly plate of and found the drive chain broken. I went out back of the shed to my OPE parts dept and pulled in a dead 524 tractor. I have acquired 4 old 24" from Craiglists free stuff. So I decided to take a chain from the most stripped one. Lo and behold, it has a master link. Life is good. The link is 3 pieces. the 3rd piece is a spring steel retainer. AKA as geezus, As in " geezus where did that clip go? Despite putting it safely in my pocket , it was nowhere to be found It was in my grasp long enough to realize it was identical to a 1 and 3 spd bicycle chain ML. I bought one at the local bicycle store after coming up empty at the ACE hardware store. I bought one. When I tried to put it on. Geezus where did it go. across the shed into the void. Undefeated, I returned and bought 2 more. the first clip flew , but this time I heard it bounce. I grabbed the light and moved some stuff. There it was, I used a pair of needle nose pliers and successfully installed the retainer. This is my first time to have to do anything to the tractor in 20 yrs of old Arienss.