97 transmission noise

I have a 97 Chevy cheyene with a 4.3 v6 with auto transmission. This vehicle has about 89000 miles on it. The transmission shifts great with no problems however a clicking noise is heard as soon as you put it in gear and lasts until the torque converter locks in shortly after 3rd gear. The noise is much louder on hot days, but for the most part its not all that loud. I have not made any attemps yet to troubleshoot this problem, but it sounds to me like something may be going wrong with the torque converter. I purchased this truck recently from an elderly couple who took exceptional care of it, so im not really suspect of previous abuse. There are no other problems with this vehicle. Any suggestions????

Have you tried any tranny service? Maybe you need to change the fluid and filter.