91firehawk

It took three weeks and one day to get my truck back. The work only took a few days buy my dealer's service dept. is just all jammed up. here is what they claim to have done: "Found vehicle to have a TCC shudder present as described in bulletin #16-NA-175. Performed pan filter replacement and triple flush as per bulletin. Programmed TCM w/newest calibrations. Performed trans adapt relearn procedure and road test to learn all shifts and verify repairs. Prog code: 18D6C" after getting the truck back the vibration was gone. so for now I consider it fixed. Hopefully it does not come back.

Justin, Are you GM service tech? Is there a TSB # I can point my service dept. to so I can get them going in the right direction?

I heard back from the service manager and they agreed there is a driveline problem. They claim to have encountered this before and resolved it with a torque converter fluid flush. I believe others have had this done, but i haven't heard of anyone saying it worked. I will report back.

I have had my 2017 for almost a year now. It has very recently starting vibrating very badly at speed between 30-80mph. It feels like driving over a cobblestone road, but intermittently. Because I have added several mods I went to a friendly shop that gave me a free evaluation. They concluded it was definitely not wheel/tire balance issue and most likely a drive train problem. As such they advised I take it into the dealership for warranty. Truck: 2017, crew cab, Z71, 4X4, 6.2L and 8spd Mods: CAI, RC 2" leveling kit (front & rear) and 20" wheels w/Toyo ATII 295/55 tires. I have serious concerns they are just going to side step the real issue and blame the non-factory tires. looking at the P/N the OP used that does not seem to be compatible with my truck based on a quick search of online GM parts whole-sellers. I will need to research what P/N is for me. ******************************************************************** Any recommendations on how to find a shop that knows how to properly check for drive shaft balance and true-ness? If dealer is a bust i may go that route ********************************************************************