This is the Lego version of the Torsen Twin C (T-3), a planetary type differential with front and center differential in the same unit, in that the nominal torque split of the center is not 50:50. Building this model has been a very hard challenge, with more than 90 parts, it is probably my best model.
This unit has been mounted in my current work in progress, the Lancia Delta Integrale, which also has a Torsen T-1 on the rear axle and many more features.
The planetary gears allow to split 67% of torque on the rear axle and 33% on the front axle.

Visit my blog:	http://daniels118.altervista.org/index.php?category=26