The door check-arm is removeable, but the rivet that holds the check arm to the hinge-end of the door jamb is real hard to get out.
I can remember trying to drill a hole in the bottom of the rivet and trying to crush the bottom of the pin enough to get it out of the bracket on the front jamb. But once you get that rivet out, the check-arm can be removed from inside the door.
Get a flashlight and inspect the rollers to see if they are okay. I think there is a cotter pin of sorts holding the rollers to a bracket inside the door. Make sure that pin isn't bent. clean and lubricate the rollers.
Compare that check arm to the passenger side check arm to see if thew driver side check arm isn't worn too much to hold the door open.
Be careful to make a sketch showing how all the parts go back during dis-assembly.
If you ruin the rivet that holds the check arm to the hinge-side of the jamb, new rivets are available from repro parts suppliers, but they have a c-clip at the bottom so you don't need to crush the bottom of the rivet to keep them in the bracket.
Lube that check-arm up good with lubriplate as well as the pin thru the rollers during re-assembly. If everything's there and re-assembled properly and properly lubricated, it will outlive you.
