dwoods123

Hmm, reading this does not fill me with confidence that it is the same thing being described here in this forum. We noticed ours gets louder based upon oil pressure readings on our truck. Very strange!

Just wondering if anyone has found a manufacturer producing a fiberglass shell for these trucks yet? A.R.E. I hear is pretty close. I'm in Idaho so we are limited on brands but could drive to get one.

Ours pulled to the right and we just had it aligned at the dealership under warranty. (They only do alignments on new vehicles if under a certain mileage) It was off a little and now it seems fine. Time will tell.

This was on another forum.... As promised here is an update on my previous post regarding the thumping/knocking noise many are experiencing with the 2020 GM Duramax. After having my new truck in the shop for two weeks and the Dealership tearing down the top end of the engine to complete adjustments to the valves, the Dealership advised that the problem was related to the clutch in the fan. I was surprised with this as one of the first things they did when they first started to diagnose the problem was run the truck with the drive belt removed which they did with no change in the knocking noise. So I have the truck back and have been told that they are now waiting for a plan for repairing the problem from GM. I will update this tread as soon as I hear what the plan is.

Ours is a 2020 GMC 2500HD SLE Duramax that we custom ordered. It was the first SLE in the dealership in December and the noise has been there from day one at 7 miles on the truck.

If it is, why do some 2020 Duramax's have and some do not? Some are much quieter as well but still have it. Why are there so many different answers from dealers across the country saying all kinds of things? We are hoping it is normal too and our new truck lasts for years but it is a nail biter for sure when you spend that kind of money!

Thanks for the update! Good to know they did not find any major damage but I was sure hoping the knock would be gone. Ours is still as loud as ever but does not seem to be causing any other issues. Put over 1200 miles on it last weekend with no issues. Love the 10sp tranny and the gas mileage we get. Going to hope it gives us years of worry-free driving!

Any news on the oil pump fixing the knock? Just wondering if that is the problem we are all experiencing.

Glad to hear someone is getting a dealer to do something about it! Let us know the outcome and if it cured the noise! Ours is back in for it's first service and to get the fender light replaced due to moisture inside of it. Hubby is going to bring up the oil pump as a possibility and tell them the bulletin they mentioned is for "ticking" not a knock. Probably will not do any good but we will keep on them!

It is on here but for "ticking". If that is the one they are referring to, it is incorrect. This is a knocking noise much louder than the ticking issue. I thought that must be the one they refer to but try and argue with them and it is a losing battle. I say get it documented and move on as at least that way, if anything comes of it, you will have proof you tried to point it out in the beginning.

Got it back from the service department after having them put the rubber strip on the roof and determining the knocking noise. They said it was normal. Said it has been around for years and nothing to worry about. We tried to argue it was a new noise for this year's model but the service writer said no, it was not. We asked where it was coming from and he gave us a vague answer of "internally in the engine". I guess at least they documented it which was the goal and if something flies apart down the road, we have proof it was looked at and deemed "normal" . He did say there was a tech bulletin out on it but I seriously believe it was an old bulletin for the ticking noise that has been out there for years. This is not the same thing..... Anyone else get the same answer?

Ours is going in Tuesday for this as well as the missing rubber strip on the roof! I will see what they say it truly is....

Keep us informed on the diagnosis or if it is "normal" lol!

Let us know if you find out anything on this. Would be good to know as it is so prevalent in these from the looks of it.

Our new 2020 Sierra 2500 HD Duramax has this too. Knocking is driving my better half crazy! Never owned a diesel before but we noticed this did not seem right. Asked the tech, sales manager and others and all say it is normal after it warms up on the 2020's. Hard to believe it but I guess I'm glad others here are seeing the same thing... Will be interesting to see if a fix comes out for it or if it is what it is!