Lots of comment chains on this issue so I'll pick the newest and speak my peace. I had a 2007 4Runner for 10 years before the repairs became overwhelming. One issue I didn't discover until there was a problem was with the rear window. I opened up the hatch panel and the metal frame for the window was so rusted it was crumbling to dust. I thought that was why they eventually started putting spoilers on the rear hatch (to channel water away from seals). Traded and got a 2018 4 Runner. Opened rear hatch a week ago and water started pouring out of the lock. Removed the plastic grip inserts and let the water drain. Looked inside and the rear hatch metal frames are rusting to pieces again.
I get that no seal can be 100% and there will be water that needs to drain. However, the drainage is so bad and slow that the moisture is destroying the metal rear window frame. That is a design flaw that I had hoped Toyota had corrected with my newer model. It does not appear to be the case. Pull out those plastic grips and make sure the inside of the hatch dries out or your rear window supports will eventually collapse.
I get that no seal can be 100% and there will be water that needs to drain. However, the drainage is so bad and slow that the moisture is destroying the metal rear window frame. That is a design flaw that I had hoped Toyota had corrected with my newer model. It does not appear to be the case. Pull out those plastic grips and make sure the inside of the hatch dries out or your rear window supports will eventually collapse.