I think its a design flaw my 2009 does this and I also sprayed silicone in the tracks and I noticed when the window was partly down there was a lot of play in the side to side movement ( window glass too small ) When I get time I"ll have the dealer look at it and if anything can be done I"ll report back with a fix.

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2009 Ford Ranger XLT 4x4 4.0 4 dr 60/40 seat mod,Bedrug,Bushwacker flares,Pioneer USB radio,Lund tonneau cover,bed X-tender,auto headlights,auto dim rear view mirror,OHC,Dual lighted visors,alarm system,power lock tailgate,K&N air filter, 2pc.window visors,EGR bed caps, Westin bug deflector,Air shocks,Aries Brush Guard,ReadyLift Levelling Kit,Goodyear 265/75/16's,Custom console, dash mat,remote start,Heated/signal mirrors KC 151 driving lights backup camera W/7"monitor blind spot cameras