After TSB 18-NA-355 Was Performed
 

2018, 2SS Camaro with K&N cold air intake, flowmaster american thunderaxle back exhaust and AFM range finder. I just had the Transmission flush TSB 18-NA-355 performed today.


I swear my engine and exhaust sound noticeably quieter after the flush. Has anyone else experienced this?

18-NA-355 and the new redesigned torque converter last month. Besides the shudder being gone, what I also notice is that the trans just behaves better in general. Not quieter but it just shifts better and more properly

The new fluid does improve shifting.. the reason for the new fluid is because the older Dexron HP was hydroscopic. So that moisture has an affect on how all the clutches apply, not just the converter clutch. Also, if it starts shifting oddly after some time I have seen the fluid temperature sensor start reading erratic which screwed up the shift adapts. Some set a code (P0711) or you can see it when graphing the TFT sensor data. They updated the trans internal harness. I feel like I am rambling.. sorry. lol

One thing I should mention is while it did fix the shudder and fluctuations in the tach, there is a very slight "grainy" feel during light throttle. Nothing that is a problem, but it does definitely exist. I know this for sure, because when I let off the throttle it feels perfectly smooth. Another way I could maybe describe it is that it feels like it's on the verge of shuddering, but never does. Hard to explain exactly. It's not something that anyone would probably notice if you never told them about the trans issue beforehand.

HCI2000SS, I'm getting the same behavior with my 2SS, in V4 mode only. At this point I'm assuming that the slight vibration feeling is normal, and perhaps that's why GM tuned the TCC to slip more in V4 mode. Anyone have insight into this?

After the flush, I was hoping that my 1-2 shift harshness would improve, but unfortunately it's still there.

Cheers- John

Yep it's definitely way more noticeable in V4 mode for me as well, but I can still detect it in V6 mode ever so slightly. It's totally acceptable, but just doesn't seem right like a good transmission should be. Know what I mean?

2016 SS 46K Miles
 

Recently bought this car and within a few days noticed the shudder. Took to dealer and the triple flush was performed but I still notice shudder. Dealer says I need to "drive car for 200 miles to complete repair." Isn't this fix supposed to be instant or can it improve over time? If still exists after 200 miles is torque converter next step? Thanks for any info

Yes, they do say drive it for 200 miles and you should notice the improvement. If that does not work, I'm assuming either a new torque converter or even a new transmission. Can anyone else confirm this?

@John703,


Try purchasing the Range finder to eliminate AFM and V4 mode, and see if it feels any different.
See the link below:
https://rangetechnology.com/afm-disabler/
PS. Make sure you buy from them so you get the latest version.

No way it should take 200 miles. If you're still experiencing it then it's not fixed...plain and simple. Did they inspect the torque converter?

As far as I know they just did the triple flush. I'm still going to wait the 200 miles just to prove to them it's not fixed

the 200 miles is for the transmission to relearn the shifting. if any work is done to the transmission, even just a fluid flush, they have to put it into relearn mode, which takes roughly 200 miles of *you* driving it for it to relearn how to shift.

Could not find many mentions of code P0711 on the forum doing a search. I had the new fluid put in about 3,000 miles ago. All had been fine since until last week. Started up to drive home and noticed the RPM gauge stuck on zero. Car drove normally. Shutting down and restarting caused the RPM gauge to do its normal “sweep” after start up but otherwise it kept reading zero. Later that day, started up again and the RPM gauge resumed normal function and continued to do so. A few days later, the check engine light came on. I figured it was related to what I had just seen. The Chevy dealer found code P0711 and replaced the transmission fluid temperature sensor. This involved removing the transmission pan and valve body and replacing the fluid again. Would have been an ugly bill out of warranty I’m sure. I have no idea if these events were related or not.

When I had the TSB #18-NA-355 flush/fill done on my Colorado it came back. My dealer said they wouldn't even look at again it before it was driven for at least 200 miles. After the 200 miles, I took it back, they called GM and GM said replace the TC. It's been about 1000 miles since the TC replacement and it seems okay now.