 On a very basic level, the SH-AWD system is combination of the Honda VTM-4 automatic all-wheel-drive system and the ATTS variable torque distribution system.Honda introduced the Active Torque Transfer System (ATTS) technology in the 1997 Honda Prelude Type SH.Honda introduced the Variable Torque Management 4WD (VTM-4) automatic all-wheel-drive system in late 2000 on the 2001 model year Acura MDX sport utility vehicle (SUV) and later on the 2003 Honda Pilot SUV.