I have just bought a 89 Jimmy, it has a TH700 trans. I'm having trouble shifting it into gear, it seems really stiff and if I try shifting from park to rev it takes so much effort to move that it ends up going to Drive. I have disconnected the cable at both ends. The shifter moves freely and the trans easily clicks between gears. the cable moves quite easily and even when connected to the column shifter it's still easy to move. When connected to the trans it becomes stiff. The truck has been converted to Right hand drive so the cable runs down the rh side of the trans then loops around the back to the gear selector on the side of the trans. Is it common for cables to stiffen up when under load? any ides?