ISO specific Dean/Cas fic

[smeggingnuts.livejournal.com]

I am looking for a specific fic.  I am sure I was reading it on AO3 I lost my bookmark and I don't remember the name of the author or fic and I can't seem to find it.

 What I remember is that is was a WIP Its has a soulmate/truemate storyline.  Also I think its Sub/Dom/Switches.  Dean is Sub. its starts off with John taking Dean when he was little and told him that Sam and Mary were dead (I think) John tells dean that people like Bobby don't like Subs so not to bother trying to contact them but John had told everyone else that Dean was dead.  John treats Dean like crap says he isn't good for anything because he is a sub.  Sets him up in a house somewhere to act as his personal research library and medic as John travels hunting.  Dean has a job as a mechnic.  I think he works with Benny.  Anyway he ends up fixing Cas' car and he turns out is Sam's roommate.  Also later in the story Dean has an accident at the shop and get run over by a car and bust his leg.  I would really appriciate help finding this its been driving me nuts for weeks