Surging Transmission

[mattsvtcobra]

I took in my 2019 AT4 with a few issues, but one is that under light acceleration, you get a push/pull sensation until you even out your gas. Another is if you floor it, it will do it especially when you get over 30 and are on an interstate onramp. Towing a 3-3,500lb boat, it is very noticeable on the interstate when in cruise and the computer is calling for more gas to speed up. 

 

I am being told that this is because I have "auto" selected and the front axle is causing this. He informed me of this 3/4 of the way through the test drive and we had just switched to him driving. So I didn't get to test it with him in the car. I'm fairly certain I have tested it before and it was present  in 2 wheel. 

 

He is telling me this is not a shuttering that the TSB is for, and that the transmission is acting as it should since I have it in auto. He is calling it "lugging,"

Edited October 30, 2019 by mattsvtcobra

[oldmann]

I actually noticed this feeling the other day.  I was just going down a small incline and was on level ground.  The RPM actually fluctuated about 100 rpm for 3/4 of a mile.  Weirdest thing.  This is the third time I have noticed it in 12k miles.  Could it me the torque converter locking and unlocking?  

[mattsvtcobra]

55 minutes ago, oldmann said:

I actually noticed this feeling the other day.  I was just going down a small incline and was on level ground.  The RPM actually fluctuated about 100 rpm for 3/4 of a mile.  Weirdest thing.  This is the third time I have noticed it in 12k miles.  Could it me the torque converter locking and unlocking?  

Were you in 4wd AUTO or just 2WD? The dealer is trying to tell me the front and rear are not in sync when left in AUTO and it is called lugging.

[oldmann]

2wd.  No snow here yet.

[Larry Connally]

I’ve had this happen in my 2019 duramax in  2wd and about 45 mph and just coming out of coasting down a hill. Not sure what is happening but I’ve noticed it mostly after just leaving home so nothing is really up to temperature so torque converter maybe not be locked up yet. Otherwise not sure

[mandrewbot3k]

Mine is brand new, only a week old, and I have been noticing it. I was hoping the shift points/timing are just off from people test driving it and going harder than normal. Hoping some easy driving will fix it, but it seems somewhat random. I notice it the most from 1st to 2nd and 2nd to 3rd. 

[BIGDOGx]

On 10/30/2019 at 12:21 PM, oldmann said:

I actually noticed this feeling the other day.  I was just going down a small incline and was on level ground.  The RPM actually fluctuated about 100 rpm for 3/4 of a mile.  Weirdest thing.  This is the third time I have noticed it in 12k miles.  Could it me the torque converter locking and unlocking?  

Imo that sounds like the grade braking feature activating that i wish these trucks didn't have. I know the majority of my driveability concerns with my truck stem from that stupid idiotic setting always being active upon startup.

[tony43z]

I have a 2019 AT4 6.2L and I took mine back to the dealer due to the same problem, along with it just shutting off whenever it feels like it with or without the Auto shutoff feature enabled.  They could not replicate the issue.  But yes.. My AT4 feels like it's surging going down the road in 2WD without the 4 Auto enabled.  Glad I'm not the only one.

[J2Jones]

I have a 2019 AT4 6.2 and believe I feel this on occasion too.  Would agree that it's erratic.  I don't notice much with on ramps under consistent acceleration but definitely in traffic where it's more stop and go.  Also occasionally when leaving stop lights.  It's almost like it "lunges" towards the car in front of me.  Can be disconcerting if the other driver hesitates.