Just driving down the highway, not accelerating or braking, cruising smoothly along at about 62 mph and 2,600 RPM (2004 A6 2.7T Automatic Tiptronic) and all of the sudden BONK...it felt like I hit something, but I didn't. Same thing happened last night too.

Feels like the transmission tried to temporary lock-up and then momentum and horsepower took over again and overcame the issue. Scared the crap outta me.

During the last service about 2 weeks ago; I replaced the tranmission fluid and filter; plus gear oil too....using kit and products from ESC Tuning. Royal Purple, etc.

The engine itself was running just fine, so it's not an intake or injection issue. And it's not the brakes either; they're fine.

Anyone else seen an issue like this?

 

ps: car is chipped by APR, stock exhaust, forge diverter valves, etc. stock turbos. timing chain has been replaced. cam seal oil leak is present, but has not been fixed yet.

here's a link to the transmission maintenance kit that I bought from ECS Tuning and had installed by Induktion Motorsports in Maryland.