We had a good rain which let me see that there are still three (possibly only 2) leaks inside the cab.
1. The first one is up the driver kick panel (up too far for me to see) but not from the lower corner of the windshield (pulled off the molding/trim to check). I am looking for guidance on where this leak is originating from and how I could address it (because there is a huge metal frame in the way). I could not get a good angle between the kick panel and the inside metal frame.
2. The second leak is at the rear window area on the driver side. I sealed the third brake light already and I am confident it is not leaking from there. Should I just go ahead and replace the rear window seal (as it is the likely reason for the leak). The first picture you can see where the drop of water is pooling into a drip.

Curious about under the rear window... The metal is double walled for a few inches under the window and inside seems to be partially filled with some type of insulation or something. Is there a way to get that out because I can see that it has retained water in the past because the screws and holes are are rusted/rusty.

 

The cast Aluminum part is the steering column support. The most-likely cause of a rain leak in that area is always the windshield sealant. Remove the inside & outside trim, clean the outside channel with a long-bristle brush & garden hose, and check inside for the highest location that you see water. Adding brightly-colored chalk powder (like from a hardware store for a chalk-line) to the water may make it easier to find - especially after the water dries.

I don't think you can buy a new rear window gasket, but even if you can, I still wouldn't change it until you've pinpointed the leak. Nor would I try to dig out the seam sealant, unless it's the leak point. If you suspect the gasket, remove & clean it. It's fairly easy - read this & the NEXT several captions:

(phone app link)


The same thing works on pickup rear windows.

 

mine had a leak at the very center on top and i used window instllation urethane and it sealed up and i made it presentable

 

Steve83 thank you for more great guidance and information. Below is a link to Steele Rubber Products which does have some good products for the OBS trucks. I was thinking of pulling out the back window, cleaning and sealing the metal track, rust proof/paint as needed, and install the window with the new gasket. I figure that I should just replace the gasket/seal since I have the interior taken apart and out of the way (as well as repairing some small dents). Thanks again for your guidance and quick responses.
https://www.steelerubber.com/search?...ded-cab-pickup

 

Time to buy a windshield trim removal tool.