Squeeky rear window

[DRTYFN]

Don't feel bad, both of my back windows do that!!! But in my case, it happens when I roll the windows down a few inches. I've had my techs look at them and they've tried to take the window tracks out & put them back in, and adjust the regulators, but no luck. I think they said the next step is to replace the regulators.
My personal opinion is that there's a urathane bushing somewhere that's the culprit. I'm sure my techs will solve the problem.