i was just out in town driving my truck and it started acting very funny, it would accelarate by itself, i wouldnt even put my foot on the gas petal and it would be flying,then i park at hardees, i put it in park and the engine sounded like i was just laying on the gas, and i didnt have my foot on the petal at all, then i pulled out and it delayed shifting into reverse and kicked very hard, what kind of transmission problems could i be having, also i could hear a clanking from underneath the truck, please help, im very concerned.