Case in URL's basically have to be treated as separate pages. UNIX is case-sensitive, while Windows isn't. SE's need to respect the fact that they can be separate pages. "Value" is not automatically/neccessarily going to be transferred from one to the other much like a canonical URL might since this is not a canonical issue.

Internally (navigation), making the changes isn't going to pose the problems. It's any external links that can pose them. The thing to do is to redirect one to the other ie. all the upper case URL's to the lower case ones. Once all internal linking is changed to be consistant, any external links will be redirected to the preferred case URL's.

As far as ranking problems, sure there can be. My site went from over 1K of indexed pages to less than 300. After making the case changes, the pages started getting reindexed. In my instance, the problems were being created (for the most part) by internal linking and not external.

Dave

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