I finally got my Bit Char-g WRX!

But I also got a gear set. if i use one of the gears i have to use a whole new axle. But the only problem is that the normal axle is gold. It looks retarted with one gold and one chrome like axle. is there any way to just change the gear and save the axle? So I can just somehow use the old axle and use a new gear ratio?