GV80 Soft Jerking Sometimes While Coming To A Stop Or Accelerating Back

[raheelbarlas]

My GV80 2020 2.5T run fine over all on high speeds but when aplying brake as if the car is coming to a stop or when accelerating back sometimes it start soft jerking in between and then goes all smooth again. I have been struggling to understand this problem. It doesnt happen everytime but happens a lot of times when in traffic driving. I have seen a TSB of differential lock nuts which i already tighten from a garage but still this issue is happening. Back shock absorbers are brand new front all ok. No OBD codes showing issues of any trans or engine or any other sort. Its annoying. Can you kindly guide what are the possible reasons? Would be a great help

Please note, I have changed all spark plugs recently, 4 tyres, 4 genuine brake pads replaced recently with discs skimmed, 2 back shock absorbers (original) changed, zero OBD code issues, no bush under the car cracked or in suspensions. 85k km driven

There is a only one very minor leak from the engine oil filter area from the engine body seal side. which i am getting fixed coming Saturday along with 10k km oil change.

Do you think (though the trans oil is life time as per genesis) I should change the trans oil? is that really a transmission problem?

Has someone experience this issue? Its frustrating a bit for such an expensive and luxury car.

 

[Jhon]

Are you sure you got the model year right?

 

[G-146957]

Are you sure you got the model year right?

Yes this is whats written on my side of driver door with VIN

 

[raheelbarlas]

Jhon - Yes its 2020 GV80 Prestige model 2.5T AWD Korean specs.

 

[Jhon]

Yes this is whats written on my side of driver door with VIN

OK, I am in the USA and the first model year we had for the GV80 was the 2021.
That was also the case for my Q5, I had a 2018 model which was a brand new build, but in Europe the 2017 was the new build.

 

[raheelbarlas]

OK, I am in the USA and the first model year we had for the GV80 was the 2021.
That was also the case for my Q5, I had a 2018 model which was a brand new build, but in Europe the 2017 was the new build.

Yes thats the case indeed for me. Any idea on the issue i mentioned?

 

[Jhon]

Yes thats the case indeed for me. Any idea on the issue i mentioned?

No, What caught my interest is that with my Audi, I had a similar issue. When I would come to a slow stop, the car would shutter a little before it stopped. Nothing really bad, but noticeable. In the Audi forums, there were a few other people with this issue, but most did not have it. I just assumed it was a transmission issue. It really was not an issue, but it just bothered me. I had it to the dealer several times but nothing. That's one of the reasons I got ride of it when the warranty was up.

 

[JohnnyBs25Prestige3.5T]

Here's my theory on this. Most, if not all, modern automatic transmissions have a torque converter (TC) that is able to be locked-up after the car gets into a certain gear when accelerating which reduces drivetrain losses and improves MPG. During deceleration / braking, the transmission controller will un-lock the TC at some point (I don't know what that point is supposed to be for your car). It may be possible that the TC remains locked until the car has slowed to nearly a stop, and since the transmission most likely has downshifted to a low gear by this point and the engine is near idle RPM, you now have a "herkey-jerkey" situation where the springiness of the drivetrains (crankshaft locked to the transmission) allowing an oscillation to commence (pretty common on manual transmission cars until the clutch is disengaged) until the TC unlocks. Torque disturbances caused by a downshifting transmission can both aggravate this and be felt as jerkiness too.

I suspect your car may have a TC that doesn't unlock quick enough to avoid this sensation during deceleration. This could be a controller issue (firmware update required??) or a mechanical issue (sticking internal TC lockup clutch).