2022 GMC 2500 HD 6.6 Gas 6 SPD 4x4 "Thud or felt motion after stopping"

Twayne77 · October 19

I'm reaching out for any help y'all might be! Been to dealership for the 2nd time with my 2022 GMC SLE 2500 HD crew cab 4x4 6.6 gas with 6 spd 6L90, 63,000 miles.

1st time I drove it with a shop guy & he agreed there was "something" there or going on, but not sure, maybe rear end/differential? Could not get a scheduled appt for 12 days & of course the issue stopped about 2 days before the appt date & I was not able to recreate it. After two days of driving it they said to come and get it, nothing wrong. Thankfully, no charge & I agreed it was not doing it. Fast forward about 3 weeks and 450 miles & it's returned!!!

This occurs in D or R and nothing at the start of movement, but after full braking and MPH is 0, all movement or motion has stopped, foot still solid on the brake in gear.....anywhere from 2 to 7 seconds later there is a "thud" or "movement" not heard, but felt in the entire cab. Strong in the steering wheel, but GMC service manager in the back seat of crew cab can feel it, service tech driving it around the service dept parking lot can feel it, and I sitting in passenger seat can feel it.

Does not occur 100% of the time, but close to 85 or 90% of the time. Seems more prevalent in R & maybe a bit stronger. There are random times that it will "thud" or be felt twice, a harder motion at the 2 to 3 second mark after the complete stop, but then another 2 to 3 seconds later a "lighter" or "softer" version of the same energy???

In the driver seat, you would say it's behind you. In the bed of the truck laying on top of the gooseneck ball hole, over the rear axle you think its towards the back glass. As mentioned earlier, you can feel it all over the truck.

Might do this 5 times in a row & then not be felt the next 3 times and then do it again on #4? Can feel it many times at a stop sign or light as you pull up and stop, but the truck is not moving. Have watched the tires in mirror many, many times & 0 movement with foot hard on the brake. GM tech was doing it this evening, and popped into N from either R or D, while applying brakes & once at a complete stop, "thud" it will still do it. When I got home, I tested it by shifting really quick into Park and keeping foot on the brake & it can still do it????

Hope this sounds like an issue someone else had & can point me in the right direction!! Both the older service tech & the service manager are stumped and not sure even where to start

Edited October 19 by Twayne77
Typo

Twayne77 · October 25

Just to update in case someone is also in need, believe this is an issue in my fuel tank. The "motion" or "movement" is noticed only when at or below 3/4 of a tank & begins to fade out at around 5/8 of a tank, and goes away below 1/2 tank.

I reported back to Jimmy at my GMC dealership & was glad to hear I might have figured it out. Offered not assistance to dig further into this, "It won't quit on you, just because something is loose or moving inside the fuel tank." "Maybe some day you can pick up a nicer fuel tank & swap them out?"

Who our why would anyone want to swap out a fuel tank on a 2022 GMC with less than 65,000 miles???

newdude · October 28

On 10/19/2024 at 1:06 AM, Twayne77 said:

I'm reaching out for any help y'all might be! Been to dealership for the 2nd time with my 2022 GMC SLE 2500 HD crew cab 4x4 6.6 gas with 6 spd 6L90, 63,000 miles.

1st time I drove it with a shop guy & he agreed there was "something" there or going on, but not sure, maybe rear end/differential? Could not get a scheduled appt for 12 days & of course the issue stopped about 2 days before the appt date & I was not able to recreate it. After two days of driving it they said to come and get it, nothing wrong. Thankfully, no charge & I agreed it was not doing it. Fast forward about 3 weeks and 450 miles & it's returned!!!

This occurs in D or R and nothing at the start of movement, but after full braking and MPH is 0, all movement or motion has stopped, foot still solid on the brake in gear.....anywhere from 2 to 7 seconds later there is a "thud" or "movement" not heard, but felt in the entire cab. Strong in the steering wheel, but GMC service manager in the back seat of crew cab can feel it, service tech driving it around the service dept parking lot can feel it, and I sitting in passenger seat can feel it.

Does not occur 100% of the time, but close to 85 or 90% of the time. Seems more prevalent in R & maybe a bit stronger. There are random times that it will "thud" or be felt twice, a harder motion at the 2 to 3 second mark after the complete stop, but then another 2 to 3 seconds later a "lighter" or "softer" version of the same energy???

In the driver seat, you would say it's behind you. In the bed of the truck laying on top of the gooseneck ball hole, over the rear axle you think its towards the back glass. As mentioned earlier, you can feel it all over the truck.

Might do this 5 times in a row & then not be felt the next 3 times and then do it again on #4? Can feel it many times at a stop sign or light as you pull up and stop, but the truck is not moving. Have watched the tires in mirror many, many times & 0 movement with foot hard on the brake. GM tech was doing it this evening, and popped into N from either R or D, while applying brakes & once at a complete stop, "thud" it will still do it. When I got home, I tested it by shifting really quick into Park and keeping foot on the brake & it can still do it????

Hope this sounds like an issue someone else had & can point me in the right direction!! Both the older service tech & the service manager are stumped and not sure even where to start

TSB on bump/clunk after a stop: MC-10249971-9999.pdf

orchardklutzy · November 1

On 10/19/2024 at 12:06 PM, Twayne77 said:

I'm reaching out for any help y'all might be! Been to dealership for the 2nd time with my 2022 GMC SLE 2500 HD crew cab 4x4 6.6 gas with 6 spd 6L90, 63,000 miles.

1st time I drove it with a shop guy & he agreed there was "something" there or going on, but not sure, maybe rear end/differential? Could not get a scheduled appt for 12 days & of course the issue stopped about 2 days before the appt date & I was not able to recreate it. After two days of driving it they said to come and get it, nothing wrong. Thankfully, no charge & I agreed it was not doing it. Fast forward about 3 weeks and 450 miles & it's returned!!!

This occurs in D or R and nothing at the start of movement, but after full braking and MPH is 0, all movement or motion has stopped, foot still solid on the brake in gear.....anywhere from 2 to 7 seconds later there is a "thud" or "movement" not heard, but felt in the entire cab. Strong in the steering wheel, but GMC service manager in the back seat of crew cab can feel it, service tech driving it around the service dept parking lot can feel it, and I sitting in passenger seat can feel it.

Does not occur 100% of the time, but close to 85 or 90% of the time. Seems more prevalent in R & maybe a bit stronger. There are random times that it will "thud" or be felt twice, a harder motion at the 2 to 3 second mark after the complete stop, but then another 2 to 3 seconds later a "lighter" or "softer" version of the same energy???

In the driver seat, you would say it's behind you. In the bed of the truck laying on top of the gooseneck ball hole, over the rear axle you think its towards the back glass. As mentioned earlier, you can feel it all over the truck.

Might do this 5 times in a row & then not be felt the next 3 times and then do it again on #4? Can feel it many times at a stop sign or light as you pull up and stop, but the truck is not moving. Have watched the tires in mirror many, many times & 0 movement with foot hard on the brake. GM tech was doing it this evening, and popped into N from either R or D, while applying brakes & once at a complete stop, "thud" it will still do it. When I got home, I tested it by shifting really quick into Park and keeping foot on the brake & it can still do it????

Hope this sounds like an issue someone else had & can point me in the right direction!! Both the older service tech & the service manager are stumped and not sure even where to start

fireboy and watergirl are the perfect test of friendship!

Given that the dealership is stumped, you might consider asking for a field engineer or regional GM technician to take a look. These engineers often have more specialized knowledge and may be familiar with less common issues on specific models.

Edited November 1 by orchardklutzy