Window rolls down going over bumps

[MixerDriver]

I was driving into town this morning and heard something rattling on the passenger side of the cab. Then I started hearing wind noise and looked at the passenger window and saw it was slowly opening. The window crank was also turning. I hit the bump over a culvert and the window quickly disappeared into the door. I could roll it back up and it stays closed, but it starts rolling back down with the slightest jolt. Shimmed the window up, and I guess I get to pull the door panel off to see what's going on. 

 

Maybe it's a special feature...Automatic Window Roller-Downer

[Crstfr]

man.. crazy.... hope you figure it out!... lol@special feature.... .. there's a ton of those reading through all the posts!!! 

[MixerDriver]

On 3/6/2018 at 11:26 AM, Crstfr said:

man.. crazy.... hope you figure it out!... lol@special feature.... .. there's a ton of those reading through all the posts!!! 

I hope so too, but it's not high on priority since I can count on 1 hand the number of times I've used that window. 

[Mileguru]

2017 Sierra SLT Crew Cab 6.2L 8-speed

If I start to roll my window up (pull up on the button hard once so it does an automatic full roll up without me having to keep my finger lifting the button) and then go over a speed bump a second or two after it starts to roll up, it will reverse itself and roll back down on its own.

 

Zero relevance to your thread, as you have a crank window, but fun to share nonetheless. You probably just have some sort of stopper that is broken or a "gear" (if you will) that is not engaging fully and slips it's grip.