i have a 96 dodge ram ext cab.2 wheel drive 5.2 anyway when i first start the truck up and dont have a second to let it warm up i put it in reverse it makes a loud growling noise (only in reverse) if i put it in any other gear it stops. i have changed the fluid and filter. it shifts fine and always has shifted fine. its done that since i got the truck. so now i let it warm up . and sometimes i put it in neutral to warm it up and then it doesnt do it. Help would be great thanks!