I've got a 1983 F250 with the BW 1345 transfer case, and I just replaced the speedo gear in the transfer case because it was worn, as well as the driven gear because the speedometer was doing the herky jerky while going down the road. The speedo cable is also new. I got everything back together, and made it two miles before the speedo started jerking around again then just dropped to zero. When I pulled the cable from the T-case, the driven gear was toast. It was all mangled and worn down to sort of a cone shape. Does anyone have a clue what could have caused this? I'm about ready to just give up on having a working speedometer. Thanks for the help.