yes please don't touch the tamiya gears, i have tanks from 12y old never had any issue's with them, see no tearing at any place, thats the difference between HL and tamiya , quality, long lasting and price also.
I ordered a gearbox for my third KTit was from the 36 tamseries static so, it costed 60€ and it gonna last for ever ... my porsche KT is twelve years old no wear at all