have a 88 1500 with a 350 in it and had to recently replace the transmission in it. everything is back in and now i can only start and run the truck with the parking brake on. whenever i release the parking brake the truck shuts off. any help to figure this problem out would be a great help.

It sounds like there is a wiring issue. Whoever did the install didn't hook something back up correctly. Without specific knowledge of exactly what was done to your truck it's difficult to give you much help.