I'm calling the dealer where I bought and have it serviced to see if they had gotten any where with GM. three times in 54,000 to me is unacceptable. 1 once in 75,000 I could see it. I used to have a dodge ram 1500 with the 360 4x4. No.7 cylinder would always burn the electrode off the spark plug about every 10,000 to 15,000 miles. they could never figure out why. but they kept repairing it until I traded it on my chevy. I got rid of it with 138,000. I feel if you have in issue with something thats under warranty, If the problem isn't solved it should still be repaired even after it's out of warranty like my Dodge was. I didn't spend $40,000 on a truck thats mainly used as an every day driver and not even used anywhere nears it's potential to have to replace the trans lines every 15,000 miles. GM needs to step up and admit there's a problem.
thanks for the feed back. If anyone knows of a quality aftermarket company that makes trans lines, just in case GM doesn't stand behind it, I wouldn't mind knowing about it.