Scott Campbell

OK so an update on my truck in case anyone is interested. I made an appt to take it to the dealer this past Monday and drop it off. So after work I drove it home, about 30 minutes on the highway the whole way, and it shook the hell out of the steering wheel and dash about every 10-15 seconds like I was hitting rumble strips at 70 mph. I got home and reflashed the ecu and tcm with my tuner from black bear to put the stock tunes back on the truck. Drove to the dealer about 20 minutes away, still shaking the wheel violently every fifteen seconds or so on perfectly smooth asphalt. Arrived at the dealer and asked the service advisor if a tech could ride with me and observe the issue since it only happens after the truck is warmed up for about ten minutes. He rides with me for 40 freaking minutes and the vibration doesn't occur once. I was super pissed, but he said he would try it again in the morning and see if it would do it. He told me that it is most likely the torque converter and that GM makes them do a fluid flush and filter change on it as a first step to see if it will fix it. So the next morning he drove it, didn't do the vibration at all, for 30 minutes. They still went ahead and did the flush procedure and changed the filter though under warranty. The tech told me that GM says that the fluid that was originally put in the 8 speeds was the "wrong type of fluid" or something like that, and used to come in unmarked bottles. He says the new fluid that they have been told to use is marked as Mobil 1. Anyhow I got the truck back and the vibration is gone for now, been about 100 miles so we will see. Don't know how much truth there is to the story he told me about the fluid but just thought I would pass it along. The strangest aspect of the whole thing is how the vibration seemed to stop pretty much right after I loaded the stock ecu and tcm tunes back on the truck.

What's going on guys. Been doing a lot of reading about the vibration issues on these trucks. Mine seems to be a little different than the "chevy shake" that a lot of guys have. I've got a 15 Denali 6.2 8 speed that I bought last October, it currently has 48,000 miles on it. Immediately upon buying it I noticed some terrible vibration and bumps through the wheel that I knew were not normal (this is my 5th GM Truck). Naturally I started researching on the various forums and found plenty of threads and suggestions. The problem is most of the suggestions seem to be for a constant vibration at a certain speed or situation. My issue is a pretty short but intense vibration through the wheel that rattles the dash and surrounding area, but most times doesn't seem to make the entire truck vibrate or shake. It's most intense between 45-55 mph but I can feel shaking though the wheel at other speeds too. The strangest part of the issue though is that after I first bought the truck and noticed the problem, it suddenly went away after a few weeks (honestly I can't remember how long it was, but it was sometime when the weather started getting colder.) So I hadn't had the issue in about 3 months and then driving home from work yesterday, BOOM there it was again. Doesn't make much sense to me... I've seen some mentions of guys having the power steering bushings replaced under TSB, other guys mention the hydraulic body mounts could be causing it??? I don't know but I figured this is a good place to start as I'm sure some of you guys have actually read all 800 pages of this thread and maybe can make some suggestions or most likely culprits. It's really pissing me off because it makes it frustrating as hell to drive, and I love the truck but if this keeps up I won't be able to keep it. Here's a pic of her.