Is there any reason why I can't fill the cavity between the glass and the cab with black rtv silicone to prevent my power sliding rear window from leaking inside the cab? . I don't mean just a smear but fill the whole gap.
Thanks for any help.

 

It wasn't leaking where I thought it was and found that it was a plugged drain problem that was causing the flooding. Now that I have the channel drain holes opened it should work as it is supposed to. So I guess i won't need to silicone after all.

 

Drain hole in the channel? Have a pic handy?

 

No I don't but it is under the power slider hardware at the outside edge of the channel. If you pry up on the inner part of the cable holder and then push it towards the cab side(outside) it should unlock and lift out of the channel. You should be able to see the drain hole. If you take a 5/64 drill bit and run it through the hole to clear any silicone or whatever out of the hole and then fish a wire through to make sure it is clear. Take some water and pour it in the channel and you should see it come out at the bottom of the window on the outside. The just do the other side while you have this side apart cause it is easier to remove the cable holder with the other one out of the channel. Repeat and reassemble and you should be good to go.