GOVERNMENTS do not often have the benefit of economic warning signals as clear as those that are now flashing. Both Japan and Germany have become overdependent on their exports to the United States. As the dollar's exchange rate falls and their currencies rise, they are going to find it difficult to maintain their present level of sales here. If they fail to change their internal policies, they risk going into an economic slowdown at a time when the American economy has slowed. That would probably mean a worldwide recession, squandering the enormous opportunities created by the drop in oil prices.

The United States pulled the rest of the industrial world out of the 1981-82 recession by running huge budget deficits to generate demand and -- unintentionally but very generously -- transferring much of that demand to factories abroad through an overvalued dollar. It was an admirable rescue, but it has gone on much too long. The costs and strains are visible in this country's dangerous deficits and accumulating debts. The time is long overdue for this country to get its accounts back into balance. For the next several years, the United States needs to hand off to other countries the responsibility to lead the world's economic growth. There are only two candidates with sufficient industrial strength to do it.

For some time the United States has been pressing both Japan and Germany to increase their internal growth rates. Both have resisted. This dispute is central to the financial talks that have been going on here in Washington at the World Bank and the International Monetary Fund. It will also be central to the economic summit meeting in Tokyo next month.

The Japanese have been signaling a willingness, in principle, to respond. Prime Minister Yasuhiro Nakasone has been carefully preparing the atmosphere for his visit here this weekend and, beyond that, the Tokyo meeting. It will be difficult for Japan to restructure its economic growth, he says, but it can be done. He has left a good deal of doubt both here and in Japan, unfortunately, whether he has anything more specific in mind.

The Germans do not even bother to make accommodating gestures. So far they have simply shrugged off the American arguments, replying that their economy is growing well enough and no change is justified. The reality is that Germany's government is headed toward elections next January under a chancellor, Helmut Kohl, who has not been able to extricate himself from a scandal involving political contributions. Mr. Kohl's single great asset is an inflation rate that is now down to 1 percent. He evidently intends to do nothing that could conceivably lead even the most nervous voter to think that it might rise. The danger of inflation is, in fact, extremely low because of oil prices. But Germany seems paralyzed by anxiety.

Officials of high rank and reputation frequently give speeches on the need for international coordination of economic policy. Everybody knows what needs to be done. But there hasn't been much real cooperation for some time. What happens if the American growth rate stays low or, worse, goes lower? It remains to be seen whether any other countries will acknowledge a responsibility to take up the slack.