The original PTO for the x4..and x5.. tractors is BM20633. It was later replaced by BM21914. The main difference was that the original BM20633 had all of the required parts. BM21914 will work on the x4.. x5.., and was used on the x7.. series early on. The x7.. series tractors had the control module, AM120840, already installed and was not needed, so it was eliminated from the kit. If you get the new BM21914, you will need to order the control module AM120840. If you can find BM20633, the module is included. There was a later PTO kit, BM23588, released for newer x7.. series after June 2010 that will not fit the x4.. or x5.. series.
