Yes it is an RTR thing, my truck was just the same .. just buy another set of the smaller gears and pop a pair in .. personally I'd stick with steel gears .. the gear diff is lighter than the ball diff anyway !!
On a side note, I've been working with the geared diff determined to make it work for me ... in my truck it works a treat even on slippy astro with light 5000cst oil .. but the buggy is a different animal .. been working my way UP the oils ... and finally found a oil that makes it feel the same as a ball diff .. on the bench at least .. 12000 is where we're at and looking forward to trying it out at our next club meeting
