4wd/ auto problem

[Cdip01]

2021 Yukon Denali 35,000 miles

Any help would be greatly appreciated. I haven’t noticed this before but when I’m in either auto/4wd high and I accelerate there is a slight thudding or “bumpy” feeling. I goes away after I get up to speed but when I stop and accelerate again it comes back. This only happens when I’m in auto or 4wd. I thought at first it was just the condition of the road at the time because that’s what it feels like but when I switch back to 2WD it does not happen.

Took it to a dealer that was close by but they said they couldn’t “do” anything because there were no malfunction lights on.

I plan on taking it back to the dealer where I purchased it from because I had a great experience with them but they are about an hour away.

I found this forum and figured I would see if anyone has had anything similar. What’s odd is that it does this in auto which to my knowledge is 2WD and only switches to AWD when traction is needed.

Hope this makes sense

Thanks!

 

[Micahsd]

That’s a little strange. I don’t have that with my ‘21 Tahoe. When it’s in auto or 4wd I don’t notice any different noises.

Hopefully that other dealer can figure it out.

 

[Fless]

Kind of wondering if a front diff mount is not quite tight and lets the diff move around when there's a load on the front drivetrain.

All we need now are a bunch of sensors so it will set a code and some "tech" will be able to tell there's a problem.

 

[Chad G 1979]

what road conditions are you running in auto/4wd in? Just checking as your post doesnt specify. If dry or light rain, should use 2wd. Auto if road is heavy rain/patchy snow drifts/covered and 4wd if fully snow covered. Not trying to be rude just covering simple things 1st. My wife learned this about a week after our tahoe was delivered, when she was driving the canyon and she was complaining about it driving funny/ shuddered, wheels locked up whem turning corners. I went and we swapped rides on way home from where she was and about 3 miles into my drive, it dawned on me to look. Sure enough it was in 4wd, amd as soon as i out it in 2wd, it drove as it was supposed to. She was so mad at me about it too after i told her what happened. She swore i had to have done it.

 

[jepaul2198]

I just posted this. We have very similar issues.

2021 Denali - Vehicle Knock, Stutters, Surges, Rough Acceleration - In Auto Mode, After Lifting Rods Replaced

Hello, Apologies ahead of time for my first post being what it is. I'll try hard for brevity, but often my posts are long because I do not have time to make them short. I'm not a mechanic and can barely change al alternator on a 1993 K5 Blazer, I'll do the best I can. 2021 Yukon Denali...

www.tahoeyukonforum.com

My wife wants to run the car in Auto, hence that is the purpose of AUTO. The car will decide when it needs 4wd/AWD or not. Like our Land Rover did, that was the wife's requirement. It should be noted on my issue I never had a problem before they changed out the lifting rods. Now I get the exact same feeling you are talking about.

 

[BlaineBug]

In my 2019 I notice slightly more noise when in 4x4 auto mode, but this is very hard to describe. It takes more of a personal experience to describe it more than words can do.

 

[swathdiver]

I just posted this. We have very similar issues.

2021 Denali - Vehicle Knock, Stutters, Surges, Rough Acceleration - In Auto Mode, After Lifting Rods Replaced

Hello, Apologies ahead of time for my first post being what it is. I'll try hard for brevity, but often my posts are long because I do not have time to make them short. I'm not a mechanic and can barely change al alternator on a 1993 K5 Blazer, I'll do the best I can. 2021 Yukon Denali...

www.tahoeyukonforum.com

My wife wants to run the car in Auto, hence that is the purpose of AUTO. The car will decide when it needs 4wd/AWD or not. Like our Land Rover did, that was the wife's requirement. It should be noted on my issue I never had a problem before they changed out the lifting rods. Now I get the exact same feeling you are talking about.

You're going to wear out the transfer case running around in Auto all the time.