I'm having issues uploading a video through tapatalk so let me know if it works... My truck has been to the dealer 3 times for this grinding issue, the Stoneridge transmission tech keeps telling me that it is the solenoid that is making this noise.... I showed him this video and he said that doesn't sound right, but I can't go off video because you can edit it... so my truck made the exact same sound today, and he said yup solenoid... Thanks to Kori, they took my truck anyways, gave me a rental, and I think she is waving the diagnostic fee if the don't find anything... but FFS, really a solenoid. I asked him will any 6 speed make this noise, and he was like idk.... I also said does this explain why it grinds in 4th under light acceleration, he said idk you'd have to replicate it, I was like I doubt I will be able to, he goes you sure it's not your duratacs or exhaust... I'm like dude it's grinds going into reverse and in 4th gear... not exhaust ... The video shows me turning on the truck, while tranny is warmed up 120-145 roughly, this occures at anytime, but easily replicatable on a warm turn on. I got Park-Reverse multiple times, and does it everytime, sometimes its quieter, sometimes its ridiculous like that.