So i took my truck out today and after about 3 mins it just rolled to a stop even though i was on the gas. Now when i pick it up and hold it and give it gas the tires turn and everything is good. When its on the ground though you can pin it out and it wont budge. Thought maybe it was the clutch but the spring is good and like i said it works fine when the wheels arent touching the ground. any advice? please help....