Zane k

I have a 2009 gmc sierra 1500 5.3l 4x4 with 54 thousand miles and recently it seems and feels like I've been having transmission and or torque converter problems. When I'm almost to a complete stop it feels like something just locks up and I can even let my foot off the brake pedal and not go anywhere until I press the gas pedal and start kinda moving, then it feels like something releases. Any advice or help would be greatly appreciated.