R180

Does anyone know how long the background investigation takes and how in depth they get.  I actually finished school car last month, but I actually stayed at my other job an extra 2 weeks (sick leave)  because I wanted to make sure I would be able to make it through the training before letting go of my full time gig. would this be something they would hold against me.  I've asked 2 of my prior managers if they have been contacted as of yet and they both say no. So does the check focus more on criminal elements?