Planetary Gear Trains: Notes
WARNING: This page is about a different car, the 2017 Jaguar XJ, 2016 Jaguar XJ, 2015 Jaguar XJ, 2014 Jaguar XJ, and 2013 Jaguar XJ. However, it is still accessible from the selected car via links, so may be relevant.
The 8 forward gears and the reverse gear are produced by a combination of four simple planetary gear sets, 3 clutches and 2 brakes. The front two gear sets share a common sun gear. Power is output always through the planetary carrier of the fourth gearset.
Five shift elements comprising 3 clutches and 2 brakes, are responsible for all 8 forward and reverse gears. High efficiency is achieved by the use of only 2 shift elements disengaged in each gear which reduces drag and so increases the efficiency.