I did mine earlyer in the year all i could here was a water sound from behind when i turned corners, it was a pretty simple job,
i took some pics to show how much water was in there and stuff
this picture is when i had just pulled the window out its held on by some super tough sealent, u may bend the metal panel slightly getting it out.. dont worry it will bolt back in fine.
The amount of water i had trapped in the channel, luckly the seal was good and none over flowed because it would of feel straight on to the electric window plug (i guess thats why some stop working) just to be safe before i put it back i unclipped it from the metal and moved it a little higher so water wouldnt be able to get to it as easy..
from the picture it doesnt look deep but i assure u it was more just under 2 inches deep, i had a few towels ready to soak it all up
when the water is gone either end u have the drains, mine were completely filled with crap, warm water and a tap will flush it out, after i dried everything off. Took off all the old sealent, and used silocone to seal the rubber tubes and window all back up, be generous with the silocone. u dont want it to leak.. then bolt everything back up and your done ( might wanna give the window a clean, as the bit u done see is filthy) good luck