metallic tick when slowing

Shagmax · January 28, 2017

2017 Duramax, 2500 HD crew. I am hearing a metallic tick from the engine compartment (not super loud) but more like a tap when slowing from any speed when I get down to 30mph and under, until about 10 mph. I thought it might be the Exhaust brake, but it makes the sound whether or not it is on or off. Anyone here experience the same?

20SierraL8T24 · February 22, 2017

I'd go to the Duramax forum and ask this question. Only a hand full of us here with the L5P

GMCustomerService · March 9, 2017

Hello Shagmax,

We sincerely apologize for this metallic tick you’re experiencing. Have you had the opportunity to address this concern with your dealer? If not, we’d be happy to reach out to the dealership on your behalf to facilitate this process. If this is something you would be interested in, please provide us with your full contact information, current mileage and preferred dealership. https://www.gm.com/privacy-statement.html

Kindly,

Anthony

GM Customer Care

Arkansas Farm · March 11, 2017

Yes, I've experienced the exact same type of noise since I took delivery in December. While my foot is completely off the accelerator, and in process of slowing down, at the speeds you've mentioned, I've been hearing a "tapping" type noise to near stopping, then it idols quietly.....until today. My truck has less than 5k miles on it now.

Yesterday, the dealer serviced my truck for the first scheduled oil change. This morning, I remotely started my pickup inside the house, and when I walked up to the truck to get in, I noticed the "tapping" for the FIRST time while idling. I took it to my dealer, where purchased, and they are hearing it as well. Today is Saturday, and my dealer loaned me a pickup, they are going to research and check into it further Monday morning.

My small hometown dealer has been great to work with over the years, and I'm 100% confident they will take care of me, or any other customer, (one way or the other) IF they can get the help and support they will need from GM. This problem originated from the factory, and GM should have addressed it before releasing the '17's to the dealerships!

I hope to find out more about this "ticking" noise next week.

The only other problem I've had is the engine, twice now, taking off while easing up to my garage door! Luckily, both times, I was able to press the brake harder and fast enough to keep from hitting the garage door. Again, my dealer, as always, has been aggressively trying to figure out the problem, but GM has been a little slow to assist them! I'm sure it's related to the high idle, but again, it's only my opinion.

Other than what's been mentioned above, and it is common problems with the introduction of a new product (engine here), the truck is absolutely the best yet by GM,

I have been trading annually since the resale has been very good on one year old pickups.

I will try to update this post once we find out more.

Shoney · March 25, 2017

I am experiencing the same thing , also the truck drives like its in tow mode the entire time .You can press the tow button and it changes nothing ,Just adds the trans gauge . I thought it was just my truck . So I went to another dealer and test drove another 2017 GMC denali HD . it drove the same way . I bought my truck in 21-Dec-2016 ,After I drove off the lot I knew something didnt seem right . I had to go out of town for a week so when I got back i took the truck back to the dealer to have the trans looked at . the response I got was that Gm done some changes with the sequencing on the transmission because there was tons of complaints on how the 2016 and down on how it drove when pulling loads . My truck drives like i'm in manual shift and gears down hard when stopping with the metallic ticking noise . The transmission should free wheel when slowing unless your in tow mode and now its starting to go into high idle by its self . looked in the settings to see if the high idle was on and it was in the off position . I came from a ford diesel to GMC and now starting to feel like it was a mistake. I work off shore so soon as I get back home i am taking it back to the dealer again . I don't know you or anyone else has had this experience with the truck

enmity02 · April 28, 2017

I have the same ticking noise, I especially hear it at the drive thru

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TRKLGND · April 28, 2017

Common with the LML. Kinda sounds like a sewing machine. Hopefully it's the same with the L5P. Common, not an issue.

enmity02 · April 29, 2017

I didn't hear it on my '15 LML, I hear it on my '17 L5P

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tprayner · May 8, 2017

I was told by my Service folks that this was the sound of the Fuel Injectors. I have mostly noticed the sound when windoews are down and next to a building like when going throught the Drive Thru. I am interested to find out if this is Hogwash they told me.

Peterd · June 27, 2017

Have the same ticking. Dealer convinced they build the vehicle around the radio. Shocking the strange noises it makes when the radio is off.

So far it keeps keeping on and gets a mile a gallon better than the 2015 lml. If I can keep up with the def and fuel filter replacements maybe I'll learn to like the noises. Not sure about the 1500 RPM at 35, 45, 65 MPH. Shift points aid in holding the oil pressure up. Reminds me of the days we drove in second gear to have that instant fuel pedal response.

2015 was a bit more forgiving. Did not have all the strange sounds either

At least it doesn't have the shakes!

TRKLGND · August 1, 2017

It's referred to as the DMAX typewriter. I have heard it on every duramax for the past 10 years. Common and completely harmless.

OpsWest · August 23, 2017

I am experiencing the same thing , also the truck drives like its in tow mode the entire time .You can press the tow button and it changes nothing ,Just adds the trans gauge . I thought it was just my truck . So I went to another dealer and test drove another 2017 GMC denali HD . it drove the same way . I bought my truck in 21-Dec-2016 ,After I drove off the lot I knew something didnt seem right . I had to go out of town for a week so when I got back i took the truck back to the dealer to have the trans looked at . the response I got was that Gm done some changes with the sequencing on the transmission because there was tons of complaints on how the 2016 and down on how it drove when pulling loads . My truck drives like i'm in manual shift and gears down hard when stopping with the metallic ticking noise . The transmission should free wheel when slowing unless your in tow mode and now its starting to go into high idle by its self . looked in the settings to see if the high idle was on and it was in the off position . I came from a ford diesel to GMC and now starting to feel like it was a mistake. I work off shore so soon as I get back home i am taking it back to the dealer again . I don't know you or anyone else has had this experience with the truck

Noticed the same behavior. Truck feels like it's holding a gear as if it's in tow mode even though it's disabled. Mind you it shifts at the appropriate time - but seems when you get to cruising speed it doesn't want to shift up and cruise. Instead it holds a slightly higher rpm position in the same gear. 4x4 and tow mode disabled.

Not sure however if this is just normal for the Alison/L5P