*OLD* Craftsman 139.136006 opener trolley blew apart

I had a side lip fall off a cable drum and my cables then fell off. This led to the trolley blowing apart when lifting the full weight of the door. I've replaced the drums and cables and the door opens fine manually now but I'm having trouble reassembling the trolley after bending the "hook" part of it more or less back into shape. It looks like the spring on the chain drive is either broken or missing a part. I've tried putting the trolley "hook" in a number of places on the chain assembly (not sure what it is called) where the chain bolts to the cable but none of them seem right. I'll attach a pic of what it looks like now.

Is a part missing and flew off to hide somewhere in my messy garage? Am I not seeing a good way to attach the trolley to the drive chain? How does this go back together?