COMPLAINED TO DEALER ( LOCAL) ABOUT SAGGING SPRINGS AND WAS TOLD THAT REPLACEMENT WAS THE CORRECTING FACTOR. THIS MODEL (STX) HAS DIFFERENT (HEAVY-DUTY?) SPRINGS THAN OTHER RANGER MODELS. I WOULD LIKE TO KNOW THE CONTENT OF ANY TSB'S RELATING TO THIS PROBLEM. I HAVE SEEN SEVERAL TSB LISTINGS ON ALLDATA'S WEB SITE BUT CAN GO NO FURTHER.