Transmission jerking after heating up?

Tiny
CHEWYBAR14
  • MEMBER
  • 2010 AUDI S4
  • 3.0L
  • V6
  • 4WD
  • AUTOMATIC
  • 140,000 MILES
Good afternoon,

I have the vehicle listed above supercharged. I have an issue with what I believe is the transmission. When I drive the car it is smooth and there are no issues after about 20-30 minutes of driving. After this there is a ‘jerking’ just before the car comes to a stop. If I continue driving past 20/30 minutes the ‘jerking’ becomes much more violent to the point I feel like I’ve been rear ended. I’m not a mechanic or inclined in this field at all, however, I did lots of research and changed the DSG mechatronics unit myself with a brand new one from ECS tuning as that is a common issue. That did not fix the issues. I really love this car, and I’m giving up on it as where I live there is no one that wants to touch an Audi. I don’t have endless money but would love to give it a last hurrah. After also doing some more reading I think it may be the torque converter or clutch rings. Looking to for an expert opinion and really looking forward to your response. I have some videos of the car as well. Thanks a bunch!
Saturday, August 3rd, 2024 AT 4:15 PM

10 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,526 POSTS
Yes, thanks for asking, so what happens is the transmission fluid breaks down and will not allow the clutches inside the transmission to release. I would scan the car for codes in case any are stored which can help us see what the problem is, this guide can help:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

If no codes are present here is how to change the transmission fluid out so you can see what needs to be done.

Fill the ATF using the adapter until the ATF starts to leak out of the check and fill hole. So, this transmission has a fill hole on the side like the old standard transmission did. It is are many steps to remove the fluid pan so I would rig a suction device and tube to stick into the fill hole and drain as much as you can and refill with new fluid, if the transmission does better you might what to have a flush done by someone that has the flush machine.

For Automatic Transmission (S tronic / DSG)
Type: Audi recommends using Genuine Audi DSG Transmission Fluid.
Part Number: G 052 182 A2
Capacity: Approximately 7 liters for a complete change but check the vehicle's manual for the exact amount needed.

Check out the images (below). Please let us know what happens.
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Saturday, August 3rd, 2024 AT 5:40 PM
Tiny
CHEWYBAR14
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Hey Ken, appreciate the quick reply. I have fully drained the transmission fluid already when I replaced the DSG mechatronics unit. The car does not have any codes, so it makes it much harder to determine.
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Saturday, August 3rd, 2024 AT 5:45 PM
Tiny
KEN L
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Yep, you got all new sensors and shift solenoids then, the only other thing I can think of as the car gets hot the catalytic converter can become partially clogged up which will low the vacuum of the engine which the PCM will take as you are going up a hill, even coming to a stop. There will be no codes in this case as well. How is the engine power output normal? If not let's use this guide to check the cat flow and performance:

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

If one of the catalytic converters has fallen apart. It will cause low vacuum. Check out the images (below). Please let us know what happens.

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Saturday, August 3rd, 2024 AT 6:16 PM
Tiny
CHEWYBAR14
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  • 6 POSTS
Noted, I will check that and get back to you. The power output is fantastic. Lots of power never an issue with that even when it gets hot. I appreciate the help thus far! At this point I’ll check anything I can to avoid selling it.
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Saturday, August 3rd, 2024 AT 11:23 PM
Tiny
KEN L
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  • 47,526 POSTS
I don't think the cats will be the problem then, are there any codes in the system? Also, could it be the driveline that is causing it not the transmission? This is the problem with me not being able to drive it. Can you please shoot a quick video with your phone so I can hear the noise? That way I can tell for sure what's going on. You can upload it here with your response. We need to hear the noise, so we know which direction to go to help you fix the car. It takes time to upload so please be patient.
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Monday, August 5th, 2024 AT 9:01 AM
Tiny
CHEWYBAR14
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  • 6 POSTS
No codes at all unfortunately. I’ve had the odd one come up, but nothing related to what’s happening. Also, it’s not necessarily the transmission I’m only assuming... I apologize for the late response I was out of town, and I thought I uploaded but I think I made a mistake. Hope this works, thanks again! I sent 2 videos.
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Wednesday, August 21st, 2024 AT 7:54 PM
Tiny
CHEWYBAR14
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Also, to reiterate, those videos were taken after driving the car for approximately 20-30 minutes. The longer you drive the more violent those shakes and noises get. The car drives and shifts normally until it’s been driven for about that time and slowly gets worse and worse but when it’s cool it’s normal.
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Wednesday, August 21st, 2024 AT 7:59 PM
Tiny
KEN L
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Wow, yep, to me that looks like a driveshaft needs to be replaced or something is loose, the car will need to go on a rack with someone inside to shift the gears like you do to watch from underneath. Here is the area I would look at. Thanks for the videos, they help. Check out the images (below). Let us know what you find.
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Thursday, August 22nd, 2024 AT 9:41 AM
Tiny
CHEWYBAR14
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  • 6 POSTS
Yeah, it’s not good at all... What confuses me if that it only happens when it’s hot and been running for a while... I’ll see if I can get it up and send you a video from underneath.
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Thursday, August 22nd, 2024 AT 1:31 PM
Tiny
KEN L
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That would be good, this is a strange problem. It could be the transmission fluid itself has broken down; you might want to try doing a transmission service to see if that makes a difference.
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Friday, August 23rd, 2024 AT 7:12 AM

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