I have two bikes which both have Torpedo Dreigang, and I have experieced the same trouble with them both: occasionally, when riding on speed 2, there is a kind of "jump", maybe a quarter of a turn of the crankshaft, as if the claws inside the hub skipped a housing(?) on the inner wall of the hub (I'm sorry if i don't use correct vocabulary, I'm not a native speaker). With speeds 1 and 3 I never experience this, and even with speed 2 it's not all the time.
I'm almost certain that it's NOT about adjusting the little chain that goes inside the hub; I've tried adjusting it to the both extremes within the speed 2, until the jumpiness etc clearly are about the incorrect adjustment. I've also taken the both hubs apart, cleaned and oiled all the parts, but still the problem remains.
So i was wondering, does the Torpedo Dreigang hub perhaps have a "weak spot"? Both my hubs have come to me second hand, though I don't think they should be THAT old.. with "weak spot" I mean the kind of flaw that the Shimano 3-speed has, viz., if something is broken, it is almost certainly the small ledge which has snapped, and which is crucial for the operation of the brake..?