94 Chevy / GMC G20 power window issue

Have a 94 G20 van that has its windows stopping half way up and just makes a grinding noise . If I grab the window and pull it up while engaging the window switch, it will finish going up, or physically push on it, it will go down, Both of the front windows do this. Any one have this issue before? If so, what fixed it? Thanks.

I had a similar issue once in an '89 Honda accord (my first car). Mine was the passenger side window opening about 1/3 of the way, then getting stuck, and if you pushed on the window and hit the switch it would go down another third of the way. Getting it all the way down wasn't really possible.
Then, to roll it back up, I would have to pull the window in while it closed, until it got to that 1/3 point where I could let go, close the window, and not cut anyone's fingers off.
The issue was that the window was coming off track at a certain point, so it needed guidance to open and close. What I wound up having to do was take the whole inner door panel off open and close the window a few times and check everything out. There are a number of things to look for, so I would suggest doing the same thing I did. Don't wait too long either because problems like this can put strain on the motor and burn it out, or even shatter the window.