[tomcamaro1]

[Emoto]

Originally Posted by tomcamaro1

Just did the flush on my 2017 v6 rs a couple of days ago and it seems to be o.k...but, i still have a "clunking"sound when the car down shifts between 3rd and first..anyone know what this is??,,and for the people who are having their dealership refuse to change the fluid because they can't replicate the issue go back a few post and print out the tsb 18-na-355 it states clearly that all that is needed is a customer complaint, they are not required to duplicate the problem. I'm from canada and the fluid part # up here is 19418066, does anyone know if this is the same mobile 1 fluid they are using in the U.S. ?

The hard shifting or clunk is on a different TSB. 355 is for the shuddering.

[arpad_m]

Originally Posted by tomcamaro1

Just did the flush on my 2017 v6 rs a couple of days ago and it seems to be o.k...but, i still have a "clunking"sound when the car down shifts between 3rd and first..anyone know what this is??,,and for the people who are having their dealership refuse to change the fluid because they can't replicate the issue go back a few post and print out the tsb 18-na-355 it states clearly that all that is needed is a customer complaint, they are not required to duplicate the problem. I'm from canada and the fluid part # up here is 19418066, does anyone know if this is the same mobile 1 fluid they are using in the U.S. ?

I had the 8L45, too, and it did exhibit a perceptible clunk on the 3->1 shift, but only on an incline, almost never on a flat road.

The same downshift is buttery smooth on the 8L90 I run now, which makes me think this is likely a tune issue, as the lurchy downshifts in my previous trans weren't at any significant power. (My trans is tuned, but this was just the same when stock.)

18-NA-355 is for a completely different problem, so this TSB won't help you. I would ask the dealership to put the trans into relearn mode and see if it goes away and comes back again, which would point even stronger to a tune issue.

[vidkidZ]

Repeated flushing with the old fluid on my 2016 2SS in January @32k miles lasted about 10 months @45k miles. In October, the 1st flush of the new fluid failed and the shudder came back much worse.

The dealer flushed it a 2nd time with the new fluid and the problem is improved. At this time, I don't think the problem is completely resolved as it feels like there is a slight underlying vibration/wobble at highway speeds.