All-Trac is a full-time AWD system that was installed on some Toyota cars between 1988 and 2000. It was developed by the Japanese car manufacturer Toyota Motor Corporation in 1986 and was originally called GT-Four. At that time it was considered revolutionary because it featured a locking centre differential. Before then, this had hardly ever been seen in passenger cars.
All-Trac design and how it works
In the first versions of the system, the transmission output torque was fed to the centre differential, which was integrated into the front differential. Power was then distributed equally between the axles. Wheel traction was improved on all surfaces as a result. There was also the possibility to manually lock the transfer case using the “Center Diff. Lock” button located in the cabin. After it had been pressed, the axles were coupled rigidly with each other and the propshafts of the front and rear differentials rotated at the same speed.
Later, a viscous coupling replaced the centre differential.
Cars equipped with All-Trac
|Model||Production years||Trim levels which included the system||Engine capacity (l)||Engine output (hp)|
|Camry V20||1988–1991||DX, LE||2||82–140|
|Corolla E90||1988–1992||Standard and SR5||1.6||95–125|
|Previa XR10||1990–1999||DX, LE||2.4||135|