general problems of the 2016 Porsche Cayenne

While driving vehicle, noticed some slippage/clunking when turning. Took vehicle to Porsche dealer, they said transfer case needed to be replaced. Car has 12,600 original miles on it. Dealer said there was an extended warranty on the transfer case that had expired. In researching, it became obvious that there is a Porsche design problem that affected several model years for the Cayenne. As a mechanical engineer I am concerned that a transfer case failure at freeway speeds could be dangerous. Separately an auto mechanic shop opined that driving without replacing could be a safety concern. In my opinion there should have been a recall rather than a extended warranty.

At slow speed, under acceleration, the transfer case slips, and makes a thumping noise. Over time, the car has poor acceleration when trying to get up to speed with other cars. The dealer has confirmed that this is a problem with Porsche Cayennes. Thank you.

When slowing almost to a stop, and then need to accelerate, such as slowing for a yield sign, then trying to merge, vehicle is non responsive to throttle input for at least a second, or more. This has put me and others at risk because I assume I'm going to be able to accelerate when pull into traffic and am not able to. The dealer has had the vehicle but was unable to reproduce. It does not always do it, there's some combination of engine, drivetrain or fuel management it's in that does this. I have disabled start/stop mode. There are no system messages or obd errors. The dealer has said that others have experienced this and the manufacturer has told them it's "normal". It's a safety problem and I'm seeking help in getting the manufacturer to fix it. Note, I sent the attached letter to manufacturer and did not receive a reply. I called their customer support line around sept 20th and they did not offer any escalation or other action to address other than writing to their email address. I did this, and received no response.

Car lost all acceleration and engine shut completely off happens frequently. Car on separate occasion sieved and shook violently to a stop on the road multiple times.