Outer Limits 4x4 Board

Ok going to sound like a retard here bit ordering a locker for my fj73 and trying to get the correct air locker.
So my question is how do i know if its 10 or 12 bolt is it just counting the studs that hold the front third member in.

Sorry and Thank you

Mick

its the crownwheel bolts.

the 10 bolt (rd132) is the hilux/ cruiser hi pinion
the 12 bolt (rd142) is the cruiser rear and front low pinion diffs up to the 5 wheel stud diffs came along