I have a 2000 S70AWD with 30,000 miles that has developed the strangest problem. After coming to a complete stop, accelerating normally, and arriving at about 30-50mph, the car makes a clunking noice and feels like it has just hit a bump, almost the sensation that it has "stubbed it's toe". It does this only once as long as the car remains moving. After coming to a complete stop it will do the same thing again, only once, only after reaching 30-50mph. It does this once after every complete stop, never more, and every time. It usually occurs after reaching that speed range and holding it under little or no acceleration.

The "clunk" ranges from mild (just feels like a small bump in the road), to occasionaly fairly strong, (easily noticed, and strong enough to kind of "blip" the handling for a second and rattle the dash).

It sort of feels like the tranny trying to downshift, but not really, and there is no shift in gears (at least the tach stays steady).

My dealership is stumped, they suggested that I flush and fill the tranny, which I did at $85 with no change. They say there are no software updates or glitches with the tranny. I'm not sure they quite understand the symtoms even yet, or ever will for that matter. Their "expert" in drivetrains never heard of such a thing.

Any thoughts or suggestions would be greatly appreciated, and thanks to those who keep this forum going!

Rocket in Colorado