Okay, I swear I saw a thread on this, but can't find it now. It's raining & my headliner's soaked right in the center, have water running down the center of the windshield, and beter yet, water dripping out of my rear view mirror and grage door opener. Has to be a pretty good rain to get this going, but when it does, it runs pretty good. I do have sun roofs, but all that I have read says the sun roof leaks on the passanger's side of the vehicle. Now, the thread I think I remember seeing said something about running a bead of sealant under the rubber seal around the windshield, correct??

 

Your window frame is rusted, so is mine, mine leaks too but not that bad because I went to AutoZone and bought a tube of windshield sealant, stuck a puddy knife between the rubber window seal and the roof to hold it back, ran a new bead of sealant the whole length of the glass, then I used black electrical tape to hold the seal to the roof while it cured for a few days.
Now mine only leaks in a monsoon.
I will be getting the rust fixed next year.
Using the sealant will work for as long as you want it too.
How well it seals depends on how bad the rust is and how well you goop it in the right spot, I couldn't see so I just gooped the whole thing.
The tube of sealant is like $6.

 

And they also have a windshield sealant that is extra "thin" liquid, so it can get into little spots. Permatex® Flowable Silicone Windshield & Glass Sealant (65AR) - Automotive Adhesives - Ace Hardware

Permatex Flowable Sealant

 

So, I don't have to remove the "windshield finisher" rubber window seal piece to goop it all up?

 

Nope.
Just pry it back enough so you can get in there to goop it up.
If you remove the rubber seal you wont be able to goop it up, it is leaking between the seal and the frame.
If you remove the seal you will never get it back in and you will have a larger problem than you have now.

 

Well, I ran a bead in the channel made by the window finisher and the roof. I was elated to see the windshield was dry this morning after a heavy rain last night, but this afternoon, leaking as bad as before. So, let me get this straight... Should I fill the entire void to get it to stop? I saw no rust behind the finisher at all. Doesn't feel like the headliner is wet anywhere but right at the edge closest to the windshield right over the steering wheel & of course right at the rearview mirror where the irain is running down the inside of the windshield & out of the mirror itself. Do I need a bigger bead or dig deeper??

 

You wont see the rust, it is between the glass and the window frame.
I dont know how you would stop the leak other than maybe running another bead of goop.

 

Okay, time for the econo tube

 

Mine does the same thing and Spike is correct, you won't see it. My windshield is rusted and leaking as well and I also now have cancer under the two safari windows. Next spring, I plan to fix most of the cancer on the truck