[Kevin01Z28]

Originally Posted by arpad_m

Just for peace of mind I'd double-check they use the correct fluid by part number (19417577). Only saying this because there had been an earlier service procedure that required a triple flush, and that did not correct the shudder. The new (Jan 2019) TSB I linked calls for a flush machine that will suck out everything, and I don't see why they would flush 3x with this fairly expensive fluid when they have a vacuum machine. The procedure itself seems to have some overprovisioning built in already. Then again, I'm just an amateur, it's always best to ask and confirm with the pros.

The Range disabler will leave no trace behind. If I understand correctly how it works, it supplies false signals via the OBD-II port that cease as soon as you unplug it.

(Now, theoretically speaking, there could be some internal log capturing in the ECM that might indicate the previous presence of an OBD-II device. However, even then that log will not be infinite first of all, just drive the car for a while after unplugging the Range, plus searching for that specifically would take an extra hardcore tech or service manager, which is unlikely.)

I've printed out all 17 pages for the TSB 18-NA-355. I see the part number on page 17 you referenced for the fluid that is supposed to correct the issue. Going to bring it with me, highlight the fluid number so there won't be any confusion I hope.

I really need to stop reading online about it, I see a lot of customers that say the problem comes back after 1,000 or more miles and GM does nothing to actually remedy it. By that time I'm sure the TC clutches are glazed or there is significant wear to the TC solenoid and/or other valve body components, idk.

But I do really appreciate the info..!!!