can anyone tell me how the adjustable diff lock works on the sti is it adjusted through the gear box

 

no its through the driver controlable CENTRE DIFF hence the name! it works by the use of electro magnets moving bearings or somthing like that. there is a section about it on the type-r-ra.co.uk site

 

Quite simple to use actually.

In dry weather and 80% of your driving you want the diff controller wheel set all the way back towards your handbrake, dashboard indicator should a green light at the bottom (diff-free mode).

The car is set to transfer most of the power to the rear wheels hence why DCCD equipped car's will behave much like a rear wheel drive car (designed to reduce/remove understeer).

For dry weather, moving off, doing maneuvers like parking etc you will set the dccd to diff-free mode. When your pushing the car in dry weather push the diff controller wheel forward until the 2nd green light comes on the dash indicator comes on, locking the diff slightly.

For damp conditions use the 2nd green light, will stop the rear of the car suddenly breaking loose so suddenly, still slips but the front drive helps the car pull straight.

For wet conditions use the first orange light, this locks up the diff even more and is the safest option. I don't recommend using this setting in the dry, you will find the car difficult to maneuver and it can eventually wreck the diff + dccd mechanism.

For ice/snow 1st orange or 2nd orange is best and thats it really, quite simple to use. The dccd control is variable so once your used to it you can feel the diff locking as you wind up the dial and just find a setting that works best for the condition of driving.

 

Subaru Drive Performance Magazine : DCCD - Driver Controlled Center Differential
Have a read of that, it should tell you everything you need to know