i got an 05 gmc sierra z71 with 85K miles and was wondering if i am having problems with my Tq Converter. when its cold it takes about 3 miles of driving 45 and onther 2 of 65mph then finally lock in but when its warm out is seems to work fine. i normally let it warm up for about 1-2 min before i take off warm or cold outside. any suggestions would help. 30-50 degree area.