From MINIUSA:

About your MINI's ECVT Transmission.

I'm with MINI USA. The ECVT transmission continuously varies the gear ratios, by means of a primary and secondary pulley connected by a drive belt, to provide optimum performance under a wide variety of conditions. Depending on road speed and driver demand, the circumference of the pulleys adjusts, changing the ratios. Electronic controls optimize performance and detect any faults.

As a result of the singular design of the ECVT, the transmission has characteristics different from a regular automatic transmission. These are, however, normal and do not indicate a problem with your transmission.

This technology is part of what makes the MINI Cooper so remarkable. It provides the convenience of automatic shift, while enabling the more spirited motorer to manually shift through 6 speeds, enhancing that famous go-kart handling of your MINI.

If you have any questions or if we can help out in any way, you can always call us at (866)ASK.MINI.

You can read some of the issues people have had with the CVT in this post from a couple months back.