You may have done that the hard way, I believe they still have gears and trucks available for the CC II Shark.
When I had looked, they only had the whole truck. However, the same motor and worm P/N was used in a six axle truck from the same year, which had a center axle that was available with the gear. At only like $8 vs $30+ I took a chance that it used the same gear and axle size. It did so everything worked out. I then bought a whole truck as insurance after I learned about the parts sale.
Plus I like a challenge. 🙂