Hello, For about a month or so now my transmission has been acting weird. In 3rd gear and in OD it will flare up a couple hundred RPM's and than come back down to the normal RPM. This happens most of the time while driving now. Only occurs when going between 40MPH (OD engages) and 60MPH. Any ideas? 00 Silverado 5.3 185,XXX Fluid changed / filter last year. Thanks.