Automatic Very Slight Thud when Coming To A Stop (3rd To 1st Gear I think)

kkriskal · 06-27-2018, 02:34 PM

Hello,

I have a 2018 2SS Automatic transmission. When I am coming to a stop at a stop light, there is a slight, very slight thud when I come to a complete stop. I guess this is when the transmission is shifting from 3rd to 1st. Whereas, when I am near my garage and very slow already and then stop, this does Not happen (2nd to 1st I guess). My question is, is it normal (my dealer says it is normal just by listening to me because as usual no one could replicate it or feel it while sitting in the passenger seat).

It also does Not happen when I am slowing down ahead of time and coming to a very gentle stop. I don't remember this happening until 6000 miles, now at 6400 miles after several mountain trips, I can feel it. Everything else, every other shift is absolutely normal so don't want the dealer to be experimenting with my car anymore.

I also read about the TCM software update in some forum and I did also ask them about the TCM recall and they said the 2018's don't have that recall. I would really appreciate your thoughts.

I just got the service done today (regular Mobil 1 oil change and stuff). I am going on a 6000+ mile road trip starting this weekend sow will keep you updated once I run it during the trip. Meanwhile, I would really appreciate your feedback.

CAGVF84 · 07-19-2018, 02:24 PM

My car is doing the same and it started last month. The thud / pop sound would go and come back. This month it stayed and only happen when i was slowing the car down to come to a full stop. I was finally able to take it to the dealer and explain what was going. After getting funny looks from them i asked them to have a tech drive the car around the block a few times so the can repeat the issue i was hearing. Needless to say after half a block the Tech looked at me and said wow you weren't kidding. The thus sound happened at least 6 times before pulling back into the dealership.

The Tech wrote up my maintenance repair and they are sending my car over to the power train division they have and see what they find out. If nothing then it move over to the vehicle suspension division and so forth. I told the guy i don;t want the car back until it properly repair only 17K on it fully under warranty. I wanna fixed proper i don't need a small problem blowing up into a bigger money issue. For the big bucks we pay for these cars having mechanical problem is a huge issue for GM. Wanna keep customers coming back two words come to mind, "QUALITY ASSURANCE" it everything if you want folks to keep buying GM.

When i find out more details about what the Tech at dealership find i will post here thanks!

CAGVF84 · 07-20-2018, 02:11 PM

Alright just got word from the dealership after investigating it further. It was a torgue problem left rear axle nut that had come loose. The left rear axle the torque nut located near left axle meets the hub inner section then the components leading up to the wheel. They removed it and applied lock tight liquid to it and re-installed it back. The tech drove the car around a few times to make sure the sound was gone as well any other issue that might be found. Overall it was caught early so it did not turn out to become a bigger problem. Hopefully this helps anyone else out there as well

06-27-2018, 02:34 PM	#1
kkriskal Drives: 2018 2SS Triple Black Performance Join Date: Jan 2018 Location: Colorado Springs, CO Posts: 43	Automatic Very Slight Thud when Coming To A Stop (3rd To 1st Gear I think) Hello, I have a 2018 2SS Automatic transmission. When I am coming to a stop at a stop light, there is a slight, very slight thud when I come to a complete stop. I guess this is when the transmission is shifting from 3rd to 1st. Whereas, when I am near my garage and very slow already and then stop, this does Not happen (2nd to 1st I guess). My question is, is it normal (my dealer says it is normal just by listening to me because as usual no one could replicate it or feel it while sitting in the passenger seat). It also does Not happen when I am slowing down ahead of time and coming to a very gentle stop. I don't remember this happening until 6000 miles, now at 6400 miles after several mountain trips, I can feel it. Everything else, every other shift is absolutely normal so don't want the dealer to be experimenting with my car anymore. I also read about the TCM software update in some forum and I did also ask them about the TCM recall and they said the 2018's don't have that recall. I would really appreciate your thoughts. I just got the service done today (regular Mobil 1 oil change and stuff). I am going on a 6000+ mile road trip starting this weekend sow will keep you updated once I run it during the trip. Meanwhile, I would really appreciate your feedback.

07-20-2018, 02:11 PM	#3
CAGVF84 Drives: 2017 Camaro Fifty 2SS Join Date: Sep 2015 Location: Oklahoma Posts: 34	Alright just got word from the dealership after investigating it further. It was a torgue problem *left rear axle nut* that had come loose. The left rear axle the torque nut located near left axle meets the hub inner section then the components leading up to the wheel. They removed it and applied lock tight liquid to it and re-installed it back. The tech drove the car around a few times to make sure the sound was gone as well any other issue that might be found. Overall it was caught early so it did not turn out to become a bigger problem. Hopefully this helps anyone else out there as well Last edited by CAGVF84; 07-21-2018 at 05:15 PM.

07-19-2018, 02:24 PM	#2
CAGVF84 Drives: 2017 Camaro Fifty 2SS Join Date: Sep 2015 Location: Oklahoma Posts: 34	My car is doing the same and it started last month. The thud / pop sound would go and come back. This month it stayed and only happen when i was slowing the car down to come to a full stop. I was finally able to take it to the dealer and explain what was going. After getting funny looks from them i asked them to have a tech drive the car around the block a few times so the can repeat the issue i was hearing. Needless to say after half a block the Tech looked at me and said wow you weren't kidding. The thus sound happened at least 6 times before pulling back into the dealership. The Tech wrote up my maintenance repair and they are sending my car over to the power train division they have and see what they find out. If nothing then it move over to the vehicle suspension division and so forth. I told the guy i don;t want the car back until it properly repair only 17K on it fully under warranty. I wanna fixed proper i don't need a small problem blowing up into a bigger money issue. For the big bucks we pay for these cars having mechanical problem is a huge issue for GM. Wanna keep customers coming back two words come to mind, "QUALITY ASSURANCE" it everything if you want folks to keep buying GM. When i find out more details about what the Tech at dealership find i will post here thanks!

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