How likely is it that after Germany wins (or at least doesn't lose) WWII that a (preferably successful) Communist Revolution could take place? How long after Nazi victory is it the most likely?
And what are the effects?
A Nazi Germany that doesn't lose, is a Nazi Germany that defeats the Soviet Union and forces the United Kingdom or the United Kingdom and United States into stalemate. I do not believe this to be possible due to the resilience of the Soviet state, and the excess industrial capacity and productive willingness of the Soviet worker. But, let us assume this.
How long after WWII that a Communist Revolution commences depends on your definition. If you consider Communism to the system of Bolshevik inspired party organisation, then the Communist Revolution commenced prior to Nazi victory with the Yugoslavian, Soviet and Greek partisans.
If you consider Communist Revolution to be the uprising of the self-conscious working class to abolish wage labour, the commodity, class and the state; then this is contingent on the length of time it takes for the Nazi-Junker-Syndicate economy to fail. If 1933-1937 as the period to crisis is indicative, then Nazi Germany will rapidly go into a deep crisis. Whether this can be resolved by primary accumulation from German controlled ex-Soviet and Central European territory is up in the air. I suspect that there are a couple of crises worth of special extractions available.
However, given that the Italians, French, Finns, Danes, Norwegians, Romanians, Hungarians or Bulgarians are likely to be suffering as a national community from German racialist extractions before a crisis in the German working classes' living standards; then, it is more likely that the first moment of resistance is overwhelmingly Nationalist in character. Around 1951 or 1956.
Allowing Germany's economy to retreat from Nazi politics would delay this, and revert the cycle of crisis back from a bureaucratic expenditure one towards a market / capital accumulation crisis. These have a period around seven to eleven years. This would put your crises back towards 1953-1957 / 1960-1964 respectively. Such a crisis would not be resolvable through primary accumulation without a coup towards a harder line position (in itself, a symbol of crisis). So more likely there's major strike waves, as the NSDAP didn't offer a Fordist style compromise.
Such strike waves would be closer to the 1919 composition of the German and European left than to the 1933 composition, mainly, as the Soviet Union and Comintern politics have been discredited since 1945/6.
The effects of such a system wide year of revolution (1948, 1917, etc.) would either be a socialist Europe with white states being invaded by red armies; or a white Europe with workers' bastions being reduced by nerve gas, artillery and aerial bombardment.
yours,
Sam R.