No worries. I got burned by the Legacy version when the secondary gearshaft bushing started turning into shavings,lol!
It only had a couple of hours on it pulling 4 k line 15" passenger cars.
I have replaced the drive block on three of the Legacy K4 locomotives, the internal gear gets loose on the shaft, and the only possible fix would be to pull all the wheels and finagle another gear in there and get it secured to the shaft. However, that would end up costing more than just replacing the drive block! I keep a spare K4 drive block in my closet...