kevin18050

hi all can anyone please help i've fitted a new auto box to my wrx classic but the rear diff is not compattable it's winding up badly however i got two diff's with the box but have no idea which one came with the new box originaly i don't know what numbers i'm looking for on the diff the box number is tz102yb3aa-64 can anyone shed some light on this please as i can't move the car thanks in advance