I need help with a Craftsman Rear Tine Tiller?

I have a 2008 Craftsman 800 Series 14" Rear Tine Tiller. While using the machine last weekend the the Drive Control Bar would not disengage the tines. I stopped working when I realized the situation. When I went to check the problem I discovered that the idler pulley was engaged and the drive belt was pretty well torn up and will need to be repalced.
I moved the Drive Control Bar and it was evident that the cable and spring were not doing what they were supposed to. Regardless of what I did with the Drive Control Bar the idler pulley remained engaged.
So, I am curious how or if there is a way to release the idler pulley so that I can install a new drive belt. I am also curious as to how I am going to repair the initial problem?
I am not sure if the cable is bad, if the bracket that the idler pulley is mounted on is bad or if it needs lubrication? If so where do I find the information regarding the application.

The unit is a Craftsman 800 Series Rear Tine Tiller with counter rotating tines. The model # is 917.299020 purchased in July 2008.

Thank you.