How to set lower limit of window travel on a '78 D-series truck?

[Bill Crowell]

Where is the adjustment for the lower travel limit on the side windows; i.e., to prevent the window from going down too far into the door?

Here's a picture from the FSM:

 

[LocuMob]

I'd think the regulator would take care of that. Is the window out of the guide?

 

[Bill Crowell]

Doh! When I took it apart I found that the problem was a broken roller on the regulator arm.
Now there are threads on other sites about how to repair a regulator on newer Dodge trucks by using a roller from the hardware store, drilling out the stud and using a bolt instead, but since I was not sure I could find a roller that would work on our older trucks, I ordered a new regulator from Dorman. I hope the quality is OK.