Hello, I have an 8l90e with horrible clunking while engaging gears from park, and occasional down shifts are clunky and harsh. Noticeably worse when cold. Dealer wants to charge me to do a relearn, thought I would try to use use hpt first. Has anyone had success doing a fast relearn in an 8L90 with HP tuners? I logged "fast relearn status," followed instructions from scanner. Temps were above 75c, relearn innitiated, when process completed truck had only reverse and no forward gears. I had to re-flash tcm to get forward gears again. Any input would be great. Thanks.