2012 Chevy Impala - How to diagnose vehicle shudder with a Tech 2?

[bobby2175]

Have a 2012 Chevy Impala with 208K miles and have owned the vehicle since about 6K miles. I've kept up with maintenance along the way including several transmission fluid changes. The engine and transmission are original and in general, the vehicle runs great with no issues and is my daily driver.

Over the past week or two, I've noticed that sometimes, under a slow acceleration, I'll feel a little bit of shudder with a little movement of RPMs when this is happening. It's not every time and quite frankly, does not happen very often. Had about a 180 mile drive yesterday and only noticed it once or twice.

I'm trying to see if there is a way to diagnose the issue. With a tech 2, I can see the live data, but don't know what to look for to know if there is an issue or not. For example, after reading a lot on here, seems like the shudder could be the torque converter. Is there a way to confirm this with data from the tech 2?

Some additional info and things I've tried or are on my list:
Cleaned the throttle body (it was spotless)
Cleaned MAF
Found a broken PCV hose and replaced that as well as the valve
Spark plugs still have about 11K miles left before they kit 100K and I used OEM plugs when replaced
I'm sure mounts are worn and are still original
I replaced all 4 of the VVT solenoids. Had a trouble code on 1 bank and decided to just replace them all. It seems like my issues started at the same time I replaced these. I'm still skeptical that something isn't off here. Used all OEM parts. Can a bad VVT solenoid be diagnosed with a tech 2?

There are no trouble codes.

Any thoughts on where to go next?

Thanks so much!

 

[swathdiver]

Not exactly sure, you can watch line pressures and torque converter slip. If yours were mine and the trans fluid over 30K miles, I'd change it.

 

[bobby2175]

Not exactly sure, you can watch line pressures and torque converter slip. If yours were mine and the trans fluid over 30K miles, I'd change it.

Definitely close to 30K...i think I'm sitting at 26K right now. I'll add that to the list.

 

[bobby2175]

Not exactly sure, you can watch line pressures and torque converter slip. If yours were mine and the trans fluid over 30K miles, I'd change it.

@swathdiver - was thinking about collecting the transmission fluid and sending for analysis while I continue to troubleshoot. I've used Blackstone before - would you use anyone else? Also, currently have 24K on the transmission fluid.

 

[swathdiver]

@swathdiver - was thinking about collecting the transmission fluid and sending for analysis while I continue to troubleshoot. I've used Blackstone before - would you use anyone else? Also, currently have 24K on the transmission fluid.

That's who I use as well. I know some guys use another company but never really investigated it. Anyway, my next 2 samples are already paid for and we'll be taking samples from our transmissions soon as the fluid in both is over 30K miles and one has not had a sample taken before.

Last time, the fluid had 36K on it and they said the transmission fluid had about 10K of life left in it. That's all I needed to read to put the trucks on 36-42K service intervals.