Automatic Transmission Cooler problems of the 1998 GMC C1500

Events leading up to the failure are unknnow, at no time was adverse stress or strain placed on this vehicle. The problems began in November 2003 when I lost first gear in my automatic transmission. I dropped the pan to replace the filter and fluid, there were metal roller bearings and metal debree in the pan. I had to have the transmission replaced. 80,000 miles is way too young for a transmission to fail. March, my water pump began leaking, I replaced it. April, my heater core began leaking, I by passed it. May, my radiator began leaking, I had to have it replaced. The radiator and heater core are being stored for a short time for me until I can decide if I am going to begin legal class actions on the faulty cooling system on this GMC serria 1500 pickup. GMC offered no assistance.