Anyone with a 2015 6.2l with the 8 speed auto?

[Jordan18]

Just put in an order for the 6.2L NHT as well, about 2 weeks ago. Getting updates every week from the dealer since and they are waiting to receive a build date confirmation, judging from this thread it's probably going to be a considerable back order. More and more 6.2L/8speeds have shown up on the lots just in the last month here in Alberta, but the NHT equipped trucks are non existent.

 

If it's a "working out the 8 speed bugs" thing in the factory I would think the standard 3.23 geared 6.2s would be as hard to come by? I was constantly looking at GM's website the last 4-5 months and it wasn't until late January was I able to select a max tow package to build on SLTs and LTZs, at least on GM Canada's website.

 

Jordan

[BluByU14]

 

TAC == Technical Assistance Center. That's who the service department calls when they are stumped on an issue.

 

Great, I just Googled it as well. Wrote a nice little note to the service dept describing all of the issues and to contact the TAC as they are well aware of the issue with the 8L90. Will keep you guys posted. This sucks as this is my 2nd Sierra with a potential major issue. This truck was a replacement for a buy-back of my 2014 vibrating Sierra. Besides this trans issue...this truck is flawless.

[Rme2513]

Well yet again anouther problem a repeat problem at that. The boat anchor ( truck ) would not go anywhere this morning and said engin power reduced so I'm ready to see what the dealer going to say this time and this all while I'm waiting to have the transmission replaced. So let's see now probably my 20th visit to the dealer about this new 2015 50k $ truck in less then 5k miles a new front differential a new ECM and a new transmisson on order and who knows what to fix the reduced engin power message. I think this might be the end of this truck for me let's see what they have to say. Stay tuned to another exciting episode of breaking down in a brand new truck brought to you by chevrolet

[Rme2513]

My transmission is in there going to put it in tomorrow. The engin code was a TCU communication falt and its in the transmisson so it all will be new and hopefully fixed. I was told there is a bulletin out now about the 8l90 problems so if you think something is not right take it to the dealer and keep pushing. This site and the GM customer service on here helped me a lot to get my transmisson replaced and shead the light on the problems. I hope this is the end to my problems and so dose GM and the dealer.

[CptMcSaug]

My truck is to arrive Next week, I hope it doesn't have these issue

[TX14Z71]

My truck is to arrive Next week, I hope it doesn't have these issue

I wish you luck my friend.

[CounterMeasure]

Well, that didn't last long. Not even 48 hours after replacement, mines starting to clunk again. I suspect something in the learn procedures allows it to open up and start doing it.

 

Time to figure out what I am going to do next...

[Rme2513]

Well the new transmisson is in my truck and we test drove it today no noise but I still don't have it back yet when the tow truck driver came to pick it up it was locked so instead of calling someone he picked it and scratched my truck so now it will be even longer I have to wait to get my truck back. That sucks that yours started back clunking have you taken it back up there ? Let's us know what's going on. Well if I ever get my truck back its not going to mean nothing to me or am I going to be able to be proud of it after all this. The love for this truck is gone.

[evilhunter101]

My truck is to arrive Next week, I hope it doesn't have these issue

It should be fine. My 2015 SLT 6.2 and my brother's 2015 Denali 6.2 both don't show the transmission issues I've read here. I really think GM has it figured out for recently built vehicles. I also believe the only way those with transmission issues are going to get their trucks fixed is by having the transmission replaced. Poor guys.

[CounterMeasure]

It should be fine. My 2015 SLT 6.2 and my brother's 2015 Denali 6.2 both don't show the transmission issues I've read here. I really think GM has it figured out for recently built vehicles. I also believe the only way those with transmission issues are going to get their trucks fixed is by having the transmission replaced. Poor guys.

 

I *just* had mine replaced on Tuesday. Brand new transmission. Picked the truck up Wednesday morning, and now Thursday evening it has started intermittently clunking the same way it did before I took it in.

[evilhunter101]

 

I *just* had mine replaced on Tuesday. Brand new transmission. Picked the truck up Wednesday morning, and now Thursday evening it has started intermittently clunking the same way it did before I took it in.

In that case, I'd question if they actually put in one of the newer transmissions. That and, unless you're absolutely positive it's the transmission, whether your rear gear box is bad too. Unlikely, but possible.

 

If I remember correctly, there have been others in this thread who claimed a replaced transmission fixed their issues. There's no telling why it worked for them and not you; I don't think anyone will be able to explain that. Just bad luck I suppose.

[CounterMeasure]

In that case, I'd question if they actually put in one of the newer transmissions. That and, unless you're absolutely positive it's the transmission, whether your rear gear box is bad too. Unlikely, but possible.

 

If I remember correctly, there have been others in this thread who claimed a replaced transmission fixed their issues. There's no telling why it worked for them and not you; I don't think anyone will be able to explain that. Just bad luck I suppose.

 

I know Gunner99 has also had his replaced and re-developed his original issues. We've made an assumption of what he experienced and what I experienced are the same based on symptoms.

 

When I went back and looked at the repair report and read the big paragraph carefully, something popped out that I missed before. In mentions that GM is aware of the issues in the transmission, which is why they authorized the replacement "as an assembly". More importantly, it mentions that GM has not found a root cause yet. That's what Gunner99 was told as well. Now, I thought the shop foreman said they had solved the issue in manufacture, but I must have misunderstood him. At any rate, that doesn't sit well with me.

 

Also, the other difference that might be at play is that when they test drove the truck and I picked up the truck, it had been raining. Yesterday afternoon was the first time things started to dry out here, and that's when I heard the noise again. So maybe I have something binding just enough that water acts as a lube. Maybe it is just a wrong diagnosis and I got a new transmission for no real reason? I tried to test that theory by going to a carwash and power spraying the suspension and undercarriage this morning. The result of that test was picking up a big screw in a tire there that had me at the tire shop for 90 minutes getting that fixed. So results inconclusive.

 

I am convinced now this black truck is bad luck.

[Rme2513]

It's not the black I think it's just the 8 speed the second week I had the truck I got rear ended and after that I just kept getting hit with problem after problem the 8 speed has been cursed. I bet they come out with a different version of it next year

[evilhunter101]

 

 

 

I know Gunner99 has also had his replaced and re-developed his original issues. We've made an assumption of what he experienced and what I experienced are the same based on symptoms.

 

When I went back and looked at the repair report and read the big paragraph carefully, something popped out that I missed before. In mentions that GM is aware of the issues in the transmission, which is why they authorized the replacement "as an assembly". More importantly, it mentions that GM has not found a root cause yet. That's what Gunner99 was told as well. Now, I thought the shop foreman said they had solved the issue in manufacture, but I must have misunderstood him. At any rate, that doesn't sit well with me.

 

Also, the other difference that might be at play is that when they test drove the truck and I picked up the truck, it had been raining. Yesterday afternoon was the first time things started to dry out here, and that's when I heard the noise again. So maybe I have something binding just enough that water acts as a lube. Maybe it is just a wrong diagnosis and I got a new transmission for no real reason? I tried to test that theory by going to a carwash and power spraying the suspension and undercarriage this morning. The result of that test was picking up a big screw in a tire there that had me at the tire shop for 90 minutes getting that fixed. So results inconclusive.

 

I am convinced now this black truck is bad luck.

It was Gunner99 I was thinking of. I hadn't seen where his issues came back. That's too bad. I really thought they had it figured out but I guess it's just luck of the draw. All I know is at 3500 miles I still don't have any issues (knock on wood).

 

Man, that is some terrible luck catching a screw testing your theory. Might want to ask Gunner99 if the sounds diminish when it's raining. You could be on to something there. I also can't help but wonder if the transmission fluid is too thin or heavy for the 8 speeds. That's something I'd definitely not experiment with though.

 

Very sorry you guys have been having issues. I don't know how many times you've taken your truck in, but I'd have to assume the lemon laws would cover what you're experiencing at some point.

[Rme2513]

Can you beleave that this 50k $ trucks trade in value is only 37k $ when it's only 3 months old and less then 5k miles but that is coming from the dealer that I bought it from and know about all the problems with the truck so if this transmission is a repeat of the first one like others have talked about its going to have fall under the lemon law