so i want to do some work on the interior of my truck this weekend and one thing i want to get fixed is my window wont roll up quite all the way... it is electric and works fine but it just wont go the last 1/4 inch or so, it gets there then just makes a slipping kind of noise, i can put it all the way up but i have to manually lift it into place. any ideas on what this is? im thinking window regulator but then wouldnt it not work at all? maybe it just needs a adjusting?