TL,

The full-time system in TLC & LX470 has been flawless. The center differential is GEAR-based, both in TLC (50/50 split all the time) and your 4Runner's Tosen Center Diff. Gear-based center differential is very reliable (preferred by off-roading crowd) and very fast acting. In theory, it is faster acting than the vicous coupling center diff found on RX300 and Highlander AWD. In addition, it is relatively maintenance free.

The ONLY potentially negative thing about GEAR-based units is that IF you have either the front or rear AXLE withOUT traction (both front or both rear wheels spinning), then all power will go to the axle that does not have traction, which is bad. HOWEVER, the center diff on your 4runner (& TLC, LX470) has a LOCKING FEATURE, allowing you to have 50/50 split when off-roading (which will kill VSC when you lock the center diff). Therefore, it is a moot point to even talk about this "negative" aspect.

(BTW, Torsen = Torque-Sensing)

Hope this helps.