Dry/silicone lube on the guides front and back usually speeds up the window 30-50%.

The extra strain no doubt encourages the regulator breakage that were used to seeing.

once you lubricate the window, then do a race between the passenger and driver window and compare the speed.

usually, the lubrication will do the job. If the driver window is still slower. There’s a fair chance. The motor is wearing out, but it’ll usually be OK if it’s even 20 or 30% slower it doesn’t usually fail.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)