Troubleshoot Aisin AF40-6 "popping" and "knocking" shortly after flush with Amsoil SS LV ATF

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2014 Cruze Diesel with the Opel A20DTH and Aisin AF40-6 Automatic. Has 84K miles. The AF40 does not have a drain plug that allows full removal of old fluid. I had a full flush done with Amsoil SS LV ATF about 15K miles ago.

After 5K miles the car started to make a "knock" sound when on/off accelerator. If you are very gradual with the throttle input it will not do it.

Also accompanied with a "Pop" at deceleration occurring at 10 mph. Always at 10 mph.

Happens when cold or at operating temperature. Worse when warmed up.

Appears to be getting progressively worse over time. During the last service I had the mechanic check all the transmission and engine mounts, he said they were all solid. No issues with operation other than the noises. Drives and shifts normally.

Q: Is this an issue caused by the Amsoil fluid or something internal to the transmission?

Q: Anybody familiar with this or have any idea what could be causing it?
 
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Your description sounds like driveline noise to me. Some slop is taken up on acceleration then lets loose on deceleration. Like on a RWD vehicle with a worn driveshaft. Of course your vehicle is FWD.
 
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Is this a dual-clutch transmission or direct shift transmission? Either way I believe that there is something special about these transmissions and you may have used an improper fluid. Ensure that you have the correct fluid and also have a shop (or educate yourself on the procedure) do a relearn after the fluid change.
 
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It might be the machine flush that did it rather than the Amsoil.

Also, there is a drain plug for the transmission:


NEVER flush a transmission! Instead, just do the regular fluid change multiple times.

Is this a dual-clutch transmission or direct shift transmission? Either way I believe that there is something special about these transmissions and you may have used an improper fluid. Ensure that you have the correct fluid and also have a shop (or educate yourself on the procedure) do a relearn after the fluid change.

Nope. It's a real transmission :D
 

CleverUserName

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"Shortly" = 15k miles
It was 5k after per my synopsis.
It might be the machine flush that did it rather than the Amsoil.

Also, there is a drain plug for the transmission:


NEVER flush a transmission! Instead, just do the regular fluid change multiple times.



Nope. It's a real transmission :D

I didn’t want to do 10 drain and fills to get the same result. Flush is easier and more effective.

Check the inner CV joints.
I think GM discontinued the inner CVs on these and they are NLA.

Probably need to source an Opel part from Europe.
Sounds like a CV joint failure to me!

Also, are you aware of the oil pickup seal failure on these engines? Get it changed ASAP if you haven't!
CVs are NLA here in the USA.

I had the oil pickup seal replaced with the aftermarket sleeve Viton o-rings made in Poland when the transmission flush was done 15k ago.
Have the motor mounts/transmission mounts been checked for play?
supposedly all good at last service
 
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Those don't sound like trans symptoms. More like cv axles or joints and knuckles. Take it to a shop that can lift it up and start yanking and turning things. You can pretty easily find out what's loose or makes a sound when it gets turned back and forth.
 
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