sounds like the top needle roller bearing on selector shaft is seized,if you disconnect cabled,breather pipe,reverse light sw. and the ring of 10mm bolts secureng the selector housing on and remove,under the oil seal on the shaft is the bearing and you can sometimes get it free and moving again if you are careful,if not you can`t get this bearing now and you have to take the whole housing which is expensive,plenty of penetrating oil and grease and hopefully it will free off.
cdc, September 2012
