How difficult is it to change a window roller?

Window motor is starting to go out so I'm swaping it out for new one (again). Last time I changed the motor I noticed one of the rollers was cracked and did not want to stay in the tracks. So when I change the motor this time around I'm going to change one of the rollers too. How hard is it to change one of these rollers? Looks pretty stright foreward just wondering who has done this before.

http://img.photobucket.com/albums/v486/LoudLT1Z28Vert/Picture1285.jpg
http://img.photobucket.com/albums/v486/LoudLT1Z28Vert/Picture1289.jpg
http://img.photobucket.com/albums/v486/LoudLT1Z28Vert/Picture1288.jpg

Thanks

Are you talking about the one roller at the rear of the window that moves vertical? I had to pop that roller back on when it came off and it was pretty simple... If the roller is still attached, you'll need to unbolt and remove the stop that's at the top of the rear track... Then remove the two nuts on the top and one on the bottom that bolts the track to the door... Then you can fanagle the track out from the opening and be able to roll the roller off the track.. When I put the roller back on, I had to use channel lock pliers and carefully pop it back on the post... Be aware that the rear of the window may move some when you slip the old roller off the track.. You may want to prop the window up with something... I also had the window down slightly so I could reach the roller easier... If it's one of the other rollers, I have no clue and maybe someone else could help.

BTW Did you buy that roller in the HELP section at Pep Boys, or Advance etc?