We broke down on the way to Rivas from the coast. We lost all power to the rear wheel which meant it could be a couple of things. Thankfully, it was the same problem we had about 6 months ago in Bolivia so we knew how to fix it.

Do you see how the silver circle on the inside of the big black casing is completely smooth? Well, it is supposed to have teeth like the part in Austin's hand. The two pieces (when not worn down) fit together and grip each other with the teeth/splines. Since the inside one does not have any splines, the rear wheel would slip and therefore not have any power from the drive shaft.

Now look at this photo below-- the same part on the inside of the black casing now has teeth (the metal shop we found made it for us!). Now the two pieces can fit together and grip each other so that power can be transferred from the drive shaft to the rear wheel.