[Cossett]

The only thing Ive stuffed is the gear change rod in my second truck,
When I was setting up the sevo - gear change travel I bent the rod a little cause the power of the hitec I didnt set up the sevo travel properly and epa on it, not that its a big problem for me as I only wanted one gear in it and used two of the black plastic locking pins that go on the out side of the gear box,
But that was my fault not the tamiya product and then I just disconnected the gear sevo and drove the truck a few times with a load on it to find the best gear for it and locked it in.....
Sorry just realised your talking about the shaft's the the cogs go on, it just sounds like a gimick from tamiya to make you spend more money, if any thing the cogs are going to go long before the shaft will from tamiya, Ive heard of cogs going but not the shafts in the gearbox

Cheers Tracy