Mopar Muscle Association UK

Does anyone know off the top of their head what size drain key I need to remove the filler plug from my rear axle ?
I can't find it anywhere in the workshop manual and i'm guessing the guy on the parts counter at Halfords is unlikely to know either

if i remember correctly a 3/8 ratchet fits so no special tool is needed (but i may be wrong i will check tomorow)

It is either 3/8th or 1/2 " square, ratchet or breaker ar does the job perfect

Cheers guys.