Well 2nd gear is what failed in my trans. If I were you I would contact your local zf dealer, ask them for a quote on a new transmission. I paid 3,750€+VAT for a new unit from zf directly including torque converter, they do not ask for old unit. With the old unit I would send it to a transmission shop and upgrade all internals including the center diff. May as play it safe than being stranded.
my trans failed while I was in eco mode, it downshifted into second when under semi load and that was it, the engine just revved, to power wheels, trans would not engage any gear after. Oil came out really dirty. So I highly recommend anyone driving their TH hard to change the trans oil. A buddy’s urus did the exact same thing as mine at only 18k kms. Same thing, oil extremely dirty.