From Canon USA:
Thank you for using Canon products.
This notice is to proactively inform our customers of the details of the phenomena described below along with Canon’s support actions. Because we value the trust our customers have placed in us, we are dedicated to continuously improving product quality and delivering industry-leading service and support. We offer our sincerest apologies to any customer who may be inconvenienced.
Affected Products
EOS-1D X Digital SLR Camera
EOS-1D C Cinema EOS Camera
Phenomena
In some units of the models listed below, there is a possibility that the following phenomena may occur due to wear caused by insufficient lubrication within the camera’s driving mechanism.
Potentially Affected Products
NOTE: If the camera’s battery compartment contains one of the markings illustrated below, the camera is NOT affected by the phenomena described above even if the sixth digit of the serial number is one of the numbers mentioned above.
Markings of UNAFFECTED cameras
An "A" mark or a black mark on the silver bracket
Support
Potentially affected cameras will be inspected and repaired free of charge. If you own one of the potentially affected cameras please contact our Customer Support Center.
This information is for residents of the United States and Puerto Rico only. If you do not reside in the USA or Puerto Rico, please contact the Canon Customer Support Center in your region.
Please register the EOS-1D X and the EOS-1D C. By registering, we will be able to notify you via email when service updates are available.
Thank you,
Customer Support Operations
Canon U.S.A., Inc
Canon EOS-1D X Digital SLR Camera
Contact Information for Inquiries
Canon Customer Support Center
Phone: 1-800-OK-CANON, 1-800-652-2666, TDD: 1-866-251-3752
Email: carecenter@cits.canon.com
Canon EOS-1D C Cinema EOS Camera
Contact Information for Inquiries
Canon Customer Support Center
Phone: 1-855-CINE-EOS (toll free), 1-855-246-3367, TDD: 1-866-251-3752
Email: CinemaEOS@cits.canon.com