I remembered they were Razr's from another thread of yours.
A spool is just a straight shaft the outputs connect to, it acts like a locked diff. But unlike a locked diff it cannot be unlocked since it's just a straight shaft.
The manual I found for both the brushed and brushless Razr's shows cvd's. The cvd's have a dog bone end on the differential side and a cvd's on the wheel side. They can be taken apart and the shaft removed, but I don't think it will effect anything leaving them in. Up to you how much effort you want to go through.