The news comes by way of the New York Times, which quotes GM spokesman Adam Denison as saying, "I think they want to keep that one pretty close to their chest" in reference to the underlying cause of the transmission breakages.
The Tremec TR6060 sourced to send the LS3's power to the rear wheels is a popular industry choice, found in a wide range of muscle and performance cars including Chevrolet's own Corvette, but the units installed in Camaro SS models apparently have some internal flaw that lends them to sudden and catastrophic failure.
Reports of the problem emerged on enthusiast forums over the past several weeks, usually with breakage occurring during use of the built-in launch control. Owner speculation points toward the output shaft being the weak link, but GM's statement to Camaro5, one of the largest Camaro enthusiast sites on the web, didn't confirm that aspect of the story.
The statement revealed only that GM had decided to temporarily stop shipment of the car to dealers, and that an 'in production' review is being made. GM makes it clear that it is "NOT requesting vehicles be returned for any service or dealer deliveries stopped as a result of this action." Now that the problem has been located, however, GM could be on the hook to fix all of the early-build manual-transmission SSs.
Whatever GM decides to do, however, Camaro SS owners out there might want to refrain from using their traction control for hard launches for the near future to avoid a lot of downtime as their transmission is replaced.
Automatic SS models and all other Camaros are unaffected by the problem.