88m53453

I purchased an off lease 2015 Silverado crew cab this week with 17k miles on it and was fearful of the vibration issue and the radio issue, but after a long test drive and about 600 miles this week, I can say that so far I've been lucky, best of luck to all frustrated with GM's vibration

here's a question that no one has answered in another forum on this site. 2005 Sierra 76,000 miles 4.8ltr 2wd. Was driving in a heavy rain storm and the transmission began acting beyond strange. On light throttle the trans would downshift and upon heavy throttle the trans would upshift, Exactly the opposite of what it should do. Stopped, paid a toll and from that point on, it was fine. Went into have dinner for an hour, came back out and all"seemed" fine. Drove about 20 minutes and the trans began slipping badly. Pulled over , checked fluid, fluid was perfect in color and level. There was no burned smell as well. Stopped at a friend's house for a few minutes and drove the last 30 minutes home with no problem. That was 2 months ago, with no problem since. Any ideas of what to do to prevent a reoccurence, I am reasonably sure it is a water problem getting into a wiring harness somewhere, but any help on how to proceed would be great thanks