15DenaliSummit

Okay so here’s another update for you guys. Nothing happened pretty much. The engineer came out and said he didn’t hear the noise, which is absurd because you hear it every time when you get to 75-81mph under load. So they gave my truck back and said to review in 6 months. This is the third repair attempt at this dealer so a lemon law lawyer took my case and sent a demand letter to GM to force their hand in this. And Chuck, I haven’t dropped the pan and neither has the dealer. They haven’t done anything but testing. The dealer is going to try to go to bat for me and get the engineer back out and do a drive with me to hear the noise. Another JR, it’s a little strange because it does it regardless of gear, 4,5,6, and if anything it’s louder in 4 and 5.

So wanted to give an update on this, been back to my purchasing dealer and pretty much was told to pound sand by the shop foreman. So went to a third dealership that was recommended by a good friend and they have been the most helpful. The truck is currently there for the third round of testing and has been escalated to be investigated by an engineer in person. Dealer has done multiple tests and had to order a dedicated picoscope for the 6L90 to go back and forth with engineering to get where we are now. Hopeful something comes of this but I’ll post another update on what happens with it.

UWSkier I forgot about this post so I’ll give you an update. they did nothing for me but opened up a case with GM, I guess a GM engineer decided it was a normal noise so that’s all they could do for me. I’m just shy of 31k miles now and the noise is getting slowly louder, accompanied by harsh shifting in all gears now so I’m going to call the dealer tomorrow and get on their case again. This will be the third time going in for this issue and thankfully with CTs pretty stout lemon laws I can still go for it after 2 years/24k miles if the problem originally started within that period. Going to keep updating as I’m going through this round of nonsense.

Another JR, so when it first started the noise I checked the rear axle oil level, and had to add 1.5 quarts which wasn’t too lovely to find out at 10k miles. But both dealers have said that the noise is not coming from the rear axle. Where the truck is now they are saying it’s from the transmission area but can’t find where the noise is coming from/they don’t want to tear into it without GMs approval. They’re saying to take it back and bring it back when it gets worse, it’s not really installing the most confidence in them. We’re going to talk more on Monday because I’m politely but firmly refusing that “repair” and may have to start making a fuss with GM about it. A coworker mentioned he read on a facebook thread that the newer 6L90s have been having a highway speed whine very similar to mine and a transmission builder that tore into one couldnt find out why it was making the noise. So we shall see what the dealer has to say on the next steps tomorrow.

So I’ve had my 23 HD for a year and a half now, and at 10k miles a whine started at 80 mph when under load and would stop when I let off the throttle. Had a local dealer look at it and they claimed it was my toolbox…. It started getting worse and I brought it back to the dealer I bought it from, obviously without my toolbox or tonneau cover. Now it comes on at 75mph and is louder, the lead tech took a ride with me and thankfully heard the noise. But the dealer is now claiming it’s normal operation because they don’t know where the noise is coming from. Has anyone else had this noise yet and any solution to it?

I just traded in my 15 Denali HD for a 19 AT4 1500, and the non Bose system sucks in the AT4 compared to the Denali. I am looking at all the threads of upgrades on this system and just want to get some more clarity and a little more bass since the stock speakers can’t handle any. I want to try just replacing the door speakers first and going from there, possibly adding the Kicker setup that I read about on some threads. What are some good recommendations on speakers? I saw Pioneer and JBL come up but want some feedback from everyone that has modified the systems in the non-Bose trucks.

Hi guys, was driving my truck the other day and in 3rd gear there’s a shudder under normal acceleration, it’s happened a few times since on two 4 hour drives I’ve taken. The engine rpm doesn’t jump like a slip and there’s no noise associated with it, I just felt kind of a lug/shudder, it’s hard to describe. The truck has 92k on it, tranny fluid is clean and there’s no abnormal temps I see for the trans fluid gauge. What should I go looking for?