I've done everything to a Dual 80 ratchet except change the soft grip. I've disassembled/reassembled the ratchet head and I've disassembled/reassembled the flex joint. What's involved with changing the soft grip?
I've swapped a few soft grips for the older hard handles, mostly making sure the ID of the new handle is just a hair smaller than the OD of the tools shank and then putting the new handle in some warm-hot water for a while to soften it up before pressing it on. On a few I've had to drill the hard handle out slightly on a drill press to get it just right.