The O-ring (# 30735186) is listed as '15.41 x 2.21' on various web sites, so I would think that the fill hole is most likely 15mm.
I see that you are local to me in Watford. You're very welcome to borrow the narrow funnel that I bought and used last year to refill the gearbox on my XC70. Please PM me if you'd like to do this and I will reply with my address.
__________________
_______________________________________
2010 Volvo XC70 D5 SE Lux Geartronic AWD
|