No, all social differences do not lead to social divisions. It depends upon the social and political circumstances whether or not a social difference will lead to a social division. A combination of social differences along with other differences cumulatively decides whether or not a social difference will convert into social division.
For example, a combination of race and economic backwardness would constitute a social difference that might lead to social division. However, it depends on how the political parties deal with this issue and how the government responds to it. It varies from place to place. While language or religion may be a form of social difference leading to social division in a particular form of society, it may not occur in another society due to different prevailing circumstances. For example, in Belgium, even though there is linguistic form of social difference, it has not led to social division.