HomeAll RepliesReply To: 2016 Sierra 8-Spd Issue Reply To: 2016 Sierra 8-Spd Issue Sponsored September 27, 2018 at 10:45 am #509366 RichParticipant They were able to capture the issue I explained to them and ended up swapping the Transmission fluid with a synthetic, and replacing the filter, this completely fixed the issue. Sponsored Subscribe to GM Authority For around-the-clock GM news coverage We'll send you one email per day with the latest GM news. It's totally free. First Name Last Name Email Address Subscribe via Email Leave this field empty if you're human: Sponsored