I got this by 'googling' 'what is Front Torque Transfer' then I clicked on the first link, and it told me this.
The technical high spot during the 2004 Formula 1 season was BARs use of a front torque transfer system on its cars. This was a unit on the front of the chassis that linked both front wheels via driveshafts. It helped balance the braking forces, allowing the driver to brake later into a corner and with more confidence. Like any new ideas in Formula 1 it attracted the attention of the race organisers, the FIA and the other teams. However, despite being ordered off the cars at its debut in Germany, a later incarnation of the system was deemed legal. Only when BAR agreed to it being banned was the system excluded by the unanimous agreement of the teams.
BAR admits to having derived a worthwhile benefit from the device during 2004, but could not claim to be the first to exploit the idea. It first appeared on a Benetton in 1999, attracting similar attention from the organisers and other teams. Pat Symonds of Renault F1 recalls, "We first ran it in 1998 in testing. It was adapted to fit the 98 car but wouldnt have been legal for racing. It was stuck on the bulkhead and intruded into the crash area." Only when it was incorporated into the design of the 1999 car could it be raced.
The main problem the team was trying to counter was the tendency for the front wheel to lock under braking while turning into a corner. "The limitation comes from locking the inside wheel," explains Symonds. "The minute the inside wheel locks up, the car understeers at that point and misses the apex. With FTT you are able to keep that wheel turning by transferring torque across to it. The driver can go into the corner deeper, with more confidence and not miss apexes."
Maybe googling before asking? I'm sure by serahing the forums you will also find threads about this.
if you try to use the search feature on the site (top right corner) and use it to search the forums, typing in "front torque transfer system" you get these 9 matches.
search.php?keywords=front+torque+transfer+system
viewtopic.php?f=6&t=5153