[TP2SS]

My wife's '16 CTS started the shudder at 41k. I took it in immediately and had TSB 18-NA-355 done at our Caddy dealer. It's now at 62k+ and hasn't shuddered since the TSB was done. The key is getting the TSB done ASAP when the shudder starts. Not next month, not two weeks, not next week....get it done ASAP!

If you're buying an A8 car and you can't verify the TSB has been done, get it done regardless, even if you have to pay. If you're buying from a GM dealer, make the TSB completion part of the sales deal. A buddy of mine did that on a CTS he bought and dealer didn't argue, they just did it to close the deal. Or subtract $500 from any deal on an A8 car that can't be verified that's it done. That's the cost out of your pocket at a GM dealer to have it done.

DO NOT have it done anywhere but a GM dealer, and preferably one with lots of experience doing them. It takes special equipment to do it properly, and a special procedure.

I bought my SS with 1850 miles on it when it was 3 years old. I had the TSB done as a preventative measure even though it was not exhibiting the shudder. It was still under PTW at that point, so I didn't have to pay. Dealer balked a little, said they had to verify issue before they could do it, but when I pointed out the TSB where it says "no verification required, customer complaint suffices" (paraphrased), they did it at no charge.