Yes you have the auto park system if you have the Chevy Chassis. If your do a search on here using oldusedbear as the author you will find more info on this system than you ever wanted to know. The short answer is remove the side plate to the black steel rectangular box located under the stairs, look in side and you will see two pressure switches, one is grey one is green. If the green switch is wet with transmission fluid change it. Once it leaks it won't hold pressure and the brake on the end of the transmission comes on. Also check the level of the white plastic tank that holds the transmission fluid it is probably low also and needs to be topped off.
